Interim CSO

Interim Chief Sustainability Officer (CSO) Recruitment

Exec Capital provides interim Chief Sustainability Officer recruitment for UK businesses working through regulatory disclosure programmes, net zero strategy design, ESG reporting and broader sustainability transformation. Throughout this page, CSO means Chief Sustainability Officer: the executive who owns climate, environmental and wider sustainability performance and disclosure. The interim CSO market has grown over the last few years as UK net zero policy, TCFD-aligned disclosure and the ISSB’s IFRS S1 and S2 standards have moved sustainability reporting from an optional initiative to a board-level issue, with statutory requirements for larger companies and comply-or-explain rules for listed issuers.

Where a business needs immediate senior sustainability capability — to deliver a first UK SRS-aligned report, prepare for CSRD where it still applies, build a science-based emissions reduction roadmap, prepare disclosures for IPO or refinancing, or bridge to a permanent appointment — an interim head of sustainability or interim CSO with sector-relevant experience is usually the quickest route to having a senior owner in place. Exec Capital draws on a network of senior sustainability executives across mid-market, FTSE 250 and FTSE 100 backgrounds available for interim, fractional and contract engagement.

A note on titles: on some sites “CSO” is used for a Chief Strategy Officer. If you are looking for a strategy leader rather than a sustainability leader, see our Head of Strategy recruitment page and our guide on how to hire a Chief Strategy Officer. Everything below concerns interim Chief Sustainability Officers and interim heads of sustainability.

How an Interim CSO Search Works

Interim searches move faster than permanent ones because the candidate pool is smaller and more of it is available, but the steps are the same and none of them should be skipped. We agree the timetable with you at briefing, based on the start date you need and how specialised the brief is.

Why Businesses Engage an Interim Chief Sustainability Officer

Sustainability has moved into the C-suite over the last decade. What was once a CSR function reporting into marketing or corporate affairs is now, in many businesses, an executive role with direct accountability for regulatory disclosure, capital access, customer commitments and operational risk. An interim CSO is engaged in four typical situations:

Bridging a permanent appointment. Where a CSO has departed and the business cannot afford a long gap in sustainability leadership — particularly where disclosure deadlines or board reporting cycles are close — an experienced interim can step in at short notice and run the function while a permanent search proceeds. Availability depends on the profile and on the candidate’s notice on any current assignment, so we confirm realistic start dates with you at briefing.

Specific programme delivery. A first UK SRS-aligned report, a science-based target submission to the SBTi, a climate disclosure for the annual report, an emissions baseline across Scope 1, 2 and 3, a transition plan, or an ESG due diligence response ahead of M&A or refinancing — each is a defined programme that an interim CSO can lead end to end without the cost or commitment of a permanent hire.

Function setup from scratch. Many UK mid-market and PE-backed businesses are establishing a dedicated sustainability function for the first time, typically driven by investor or customer requirements. An interim CSO can design the function, recruit the team, set reporting structures and frameworks, and hand over to a permanent appointment once the foundation is in place.

Pre-IPO or pre-exit disclosure preparation. Public market listings, debt issuance and PE exits all increasingly require credible sustainability disclosures. An interim CSO with prior public market or transaction experience can lead the disclosure work that will be scrutinised by underwriters, rating agencies, prospective investors and acquirers. Our guides to executive hiring before an IPO and exit-readiness hiring in PE-backed businesses cover the wider leadership picture.

There is a fifth situation that has become more common since 2024: a credibility problem. A customer audit, an investor questionnaire, a greenwashing complaint or a rating downgrade exposes the fact that public sustainability claims are ahead of the evidence behind them. An interim CSO can review the claims, fix the data and controls, and give the board confidence about what can safely be said, without the business having to commit to a permanent structure while it is still working out what it needs.

Regulatory and Reporting Drivers for Interim CSO Demand

The growth of sustainability reporting in the UK has been the main driver of the interim CSO market. Several reporting and regulatory regimes now apply to a meaningful proportion of UK businesses. This is a summary for hiring purposes as at November 2026, not legal advice; your auditors and advisers should confirm what applies to you.

SECR (Streamlined Energy and Carbon Reporting). The UK’s SECR regime requires quoted companies, and large unquoted companies and LLPs, to disclose energy use and carbon emissions in their annual reports. “Large” follows the Companies Act size tests on turnover, balance sheet and employees (more than 250). The turnover and balance sheet thresholds were raised for financial years beginning on or after 6 April 2025, so businesses close to the boundary should check whether they are still in scope.

TCFD-aligned disclosure. The UK’s mandatory climate-related financial disclosure rules under the Companies Act apply broadly to companies and LLPs with more than 500 employees and turnover above £500m, and to traded, banking and insurance companies with more than 500 employees. Listed companies have reported under FCA rules based on the TCFD recommendations. The disclosures cover governance, strategy, risk management and metrics, and demand cross-functional input that often surfaces gaps an interim CSO can close in a single reporting cycle. The Task Force itself completed its work and disbanded in 2023, passing monitoring to the ISSB, but its four pillars still shape UK climate reporting.

ISSB IFRS S1 and S2, and the UK SRS. The International Sustainability Standards Board’s standards on general sustainability disclosure (IFRS S1) and climate-related disclosure (IFRS S2) have been adopted for UK use as the UK Sustainability Reporting Standards, UK SRS S1 and UK SRS S2, published on 25 February 2026 for voluntary use. For listed issuers, the FCA’s policy statement PS26/19, published on 30 September 2026, replaces the TCFD-aligned Listing Rules disclosures with UK SRS-based requirements on a comply-or-explain basis for accounting periods starting on or after 1 January 2027, so the first reports appear in 2028. There is transitional relief for Scope 3 emissions and for the wider S1 disclosures. Any requirement for private companies to use UK SRS would need further legislation.

FCA Sustainability Disclosure Requirements. The FCA’s SDR framework applies to UK asset managers and the labelling of investment products. Investment management businesses building or extending sustainable fund ranges typically need sustainability expertise at executive level to meet the rules. Alongside SDR, the FCA’s anti-greenwashing rule has applied to every FCA-authorised firm since 31 May 2024: references to the sustainability characteristics of a product or service must be consistent with those characteristics and fair, clear and not misleading. The FCA’s guidance on the anti-greenwashing rule (FG24/3) sets out its expectations.

EU CSRD reach into UK businesses. The EU Corporate Sustainability Reporting Directive was narrowed substantially by the Omnibus simplification package. For most UK groups, the practical position now is that they come into scope at group level only if their EU turnover exceeds €450 million, with reporting from financial year 2028; EU subsidiaries that meet the EU thresholds in their own right may have their own obligations. CSRD reporting is more demanding than the UK regimes, and where it does apply the readiness programme commonly needs dedicated executive leadership. Many UK mid-market businesses that were preparing for CSRD are no longer in scope, which changes the interim profile they need.

Companies Act section 172 and directors’ duties. Directors’ statutory duty under section 172 to have regard to the impact of the company’s operations on the community and the environment, alongside the Financial Reporting Council’s annual report expectations, increasingly requires boards to demonstrate active oversight of sustainability strategy and risk — which in turn requires senior executive ownership at CSO or equivalent level.

What this means for an interim brief

The regime that applies to you decides the interim profile you need. A listed company preparing its first PS26/19 report needs someone who has worked on ISSB-style disclosures alongside the finance team and auditors. A large private company needs Companies Act climate disclosure and SECR experience, plus the customer and lender requirements that often matter more. An FCA-authorised firm needs someone who understands the anti-greenwashing rule and can work with the compliance function; if the bigger gap is compliance leadership itself, our interim Chief Compliance Officer and fractional compliance officer services cover that hire. A group with large EU operations needs someone who has delivered a double materiality assessment. Writing the regime into the brief at the start saves weeks of interviewing the wrong people.

When to Engage an Interim CSO Rather Than Recruit Permanent

The interim model suits several scenarios better than permanent search:

Speed of deployment. Interim CSOs are often available at much shorter notice than permanent candidates, who usually have to work out a notice period after a search that itself takes a number of months. Where regulatory deadlines or transaction timelines drive the need, interim is often the only practical route. We confirm realistic start dates for the profile you need at briefing rather than promising a timescale in advance.

Defined programme scope. Where the work has a clear endpoint — a first UK SRS report, a climate disclosure cycle, a science-based target submission — a six-to-twelve month interim engagement may be the right structural fit rather than committing to a permanent role that will need to be redesigned once the immediate work is complete.

Scale or stage uncertainty. A mid-market business that is not yet certain whether its sustainability function justifies a permanent C-suite role can use an interim engagement to establish the function and decide whether to upgrade to permanent CSO or hand over to a Director-level appointment.

Specific transformation phase. Pre-exit, pre-IPO, post-acquisition integration and corporate restructuring all benefit from a senior sustainability operator with prior comparable experience rather than a permanent CSO whose profile may not match the next phase of the business.

Interim is the wrong answer when the business needs a long-term owner from day one — for example where sustainability is central to the product, or where the role must build relationships with customers and investors over several years. In those cases, start a permanent search through our CSO recruitment service, and consider an interim only to hold the fort while it runs.

Interim CSO vs Fractional CSO vs ESG Consultancy vs Permanent CSO

Clients often come to us having already spoken to a consultancy, or having been advised that a fractional arrangement would be cheaper. Each option has a place. The table sets out how we see the differences.

These options are often combined. A common pattern is an interim CSO who leads the programme and the internal team, with a consultancy carrying out specialist calculations under their direction. Another is an interim who builds the function for nine to twelve months and then hands over to a permanent Sustainability Director they helped to select.

Other ways to hire a CSO

Exec Capital runs Chief Sustainability Officer searches in every format, and each has its own page: permanent searches through CSO recruitment and Chief Sustainability Officer recruitment, part-time ongoing support through fractional CSO, and the level below the C-suite through Sustainability Director recruitment. For the broader picture of interim leadership across functions, see our interim executive recruitment service.

Skills, Profile and Day-Rate Expectations

An effective interim CSO combines technical sustainability and reporting expertise with executive-level governance experience. The profile that works in this market includes:

Reporting framework fluency. Direct experience designing or delivering disclosures under SECR, Companies Act climate disclosure, TCFD, ISSB and the UK SRS, and where relevant CSRD. The interim must be able to engage with auditors, sustainability assurance providers and reporting accountants from day one.

Board-level governance experience. The interim CSO will brief the board, present at audit and risk committee meetings, and engage directly with the Chair on sustainability strategy. Candidates without prior board exposure rarely make this work successfully.

Sector relevance. A consumer-facing retail business has a meaningfully different sustainability profile from a B2B financial services firm or a private equity portfolio manufacturer. Sector-relevant prior experience is a strong indicator of fast time-to-impact in an interim engagement.

Programme delivery track record. Strategy and policy capability matters, but interim engagements are commissioned to deliver outputs. Candidates need a track record of leading specific programmes through to completion — disclosure publication, target submission, function build-out — within defined timeframes.

Data and controls discipline. UK SRS disclosures are designed to sit alongside the financial statements, and assurance is coming. The best interim CSOs treat sustainability data the way a finance director treats the ledger: documented sources, owners, controls and an audit trail. They work closely with the CFO, and often the strongest interim candidates have a finance, audit or engineering background as well as sustainability experience.

How interim CSO day rates are structured:

• Rates are set by scope, not just title. The main drivers are the size and complexity of the business, whether it is listed or regulated, the reporting regime involved, sector expertise and how quickly the interim must start.
• Our fee is included in the day rate. When you engage an interim CSO through Exec Capital, the day rate we quote is the all-in rate you pay, with our fee included. There is no separate placement fee on top for the interim assignment.
• We give rate guidance at briefing. Rather than publish rate bands that date quickly, we tell you what the current market looks like for the profile you need, and confirm each shortlisted candidate’s rate in writing. Our C-suite salary guide covers permanent pay if you are comparing the cost of the two routes.
• Expenses and travel are agreed at the outset, particularly where the role covers several sites or an overseas parent.

Interim CSO, Sustainability Director, Head of ESG or Chief Strategy Officer?

Titles in this area are used loosely, and the title you choose affects who responds to the search and what authority they expect. This table shows how we normally distinguish the roles when agreeing a brief.

If you are searching for an interim head of sustainability rather than a C-suite CSO, we run that search in the same way. The difference is usually one of authority and reporting line rather than skills, and getting it right in the brief helps the right candidates say yes. Our Chief Sustainability Officer job description sets out typical responsibilities for the C-suite version.

What an Interim CSO Typically Delivers in the First 90 Days

Interim assignments are judged on outputs, so we agree a 90-day plan with you and the interim before the start date. The detail depends on the brief, but a typical plan looks like this.

Days 1–30: baseline and quick decisions

• Meetings with every executive committee member, the chair of the audit or risk committee, and the largest customers and suppliers where relevant.
• A review of existing commitments, reports, ratings, targets and public claims, with any greenwashing risks flagged immediately.
• An honest assessment of Scope 1, 2 and 3 data quality, sources and owners.
• Confirmation of which reporting regimes apply and the deadlines that follow from them.

Days 31–60: gap analysis and plan

• A gap analysis against the applicable regime: UK SRS and PS26/19 for listed issuers, Companies Act climate disclosure and SECR for large private companies, SDR and the anti-greenwashing rule for FCA-authorised firms, or CSRD where the group is in scope.
• A data and controls plan agreed with the CFO, including what is needed for future assurance.
• Decisions on external support: what to buy from consultants and what to build internally.
• A draft roadmap for targets and, where relevant, a transition plan.

Days 61–90: governance and delivery

• A sustainability plan with targets, owners and budget, taken to the board or its committee.
• A reporting timetable for the next cycle, and for listed companies a roadmap to the first UK SRS-aligned report.
• Team structure and recruitment plan, including the permanent role the interim will hand over to.
• Quarterly metrics so the board can track progress after the interim leaves.

For permanent appointments, our executive onboarding guide covers the wider steps; the same principles apply to interim hires, compressed into a shorter period.

Engagement and Fees

We work on interim, fractional and permanent sustainability searches, and the commercial basis differs by format. We agree the fee structure at briefing and confirm it in writing before any search work starts.

• Interim and fractional assignments are charged on a day rate. The day rate we quote includes our fee, so you see one all-in figure for each candidate. You are invoiced for days worked, and the term, notice period and any extension are set out in the assignment contract.
• Permanent searches are usually run on a retained basis for C-suite roles, with the fee structure agreed at briefing. Our guide to retained versus contingent executive search explains the difference.
• Interim-to-permanent conversion. If you want the option to make an interim CSO permanent, tell us at the start and we will set out the terms in the contract, so there is no dispute later.
• What is included. Briefing and scorecard, market mapping and approach, screening interviews, written candidate assessments, referencing, contract administration for interim assignments, and check-ins during the first months.

IR35 and contracting

Most interim CSOs work through their own limited company. Where your business is medium or large, the off-payroll working rules (IR35) put the responsibility for deciding employment status on you as the client, and you must issue a status determination statement. We discuss the likely position at briefing and can engage interims inside or outside IR35 as appropriate. The Companies Act size thresholds rose for financial years beginning on or after 6 April 2025, but HMRC’s April 2025 Employer Bulletin says this has no practical impact on the off-payroll rules until 6 April 2027 at the earliest. Our guide to IR35 rules for senior executive engagements covers the detail.

Who We Place Interim CSOs With

Our interim sustainability clients are typically UK businesses where sustainability affects revenue, cost or access to capital, and where the board needs a senior owner quickly. They include:

• Listed and pre-IPO companies preparing for UK SRS-aligned disclosure and investor scrutiny.
• PE-backed portfolio companies where sustainability is part of the value-creation plan or the exit story, often at the request of the investor; see our private equity executive search practice.
• Manufacturers and industrial businesses with significant energy use, operational emissions and capital programmes; see our manufacturing executive recruitment practice.
• Energy, utilities and renewables businesses, where sustainability and commercial strategy are closely linked; see renewable energy executive recruitment.
• Financial services firms and asset managers dealing with SDR, the anti-greenwashing rule and investor reporting.
• Real estate, construction and infrastructure businesses with building performance, embodied carbon and planning requirements.
• Retail, consumer and food businesses with large supply chain footprints and customer-facing claims.
• Family-owned and private mid-market businesses responding to customer, lender and supply chain requirements for the first time.

How We Assess Interim CSO Candidates

Sustainability is an area where the vocabulary is easy to learn and delivery is hard. Our assessment is designed to separate candidates who have written strategies from those who have carried them out. For every shortlisted interim we test:

• Delivery. A reduction target, report or programme the candidate owned, how it was measured, what got in the way, and whether it was achieved.
• Reporting and data. Whether they have built a disclosure from the ground up, worked with auditors or assurance providers, and handled Scope 3 data at supplier level.
• Commercial judgement. Whether they can make a business case for investment in terms a CFO will accept, and where sustainability has changed a product, price, contract or capital decision.
• Interim fit. Evidence that they arrive with a plan, make decisions in the first weeks, and leave behind a team and process that keep working.
• References. Taken from people who saw the work, including at least one finance or audit contact where reporting is central to the brief.

More on structured assessment is in our guide on how to hire a Chief Sustainability Officer or Chief ESG Officer.

Why Interim CSO Assignments Go Wrong

Most problems with interim sustainability assignments are visible at the start. The patterns we see most often are:

• No defined outputs. An interim hired to “lead sustainability” with no agreed deliverables drifts. Agree the three or four outputs that define success before the start date.
• Finance left out. Disclosure under UK SRS depends on finance data, controls and audit. If the CFO is not part of the selection and the plan, expect friction over numbers.
• No budget or authority. An interim responsible for targets but without control of spend, suppliers or people cannot deliver them.
• No plan for the handover. Decide early whether the interim will hand over to a permanent CSO, a Sustainability Director or a fractional arrangement, and start that search in time.
• Choosing fluency over delivery. The candidate who talks best about frameworks is not always the one who has moved a number in a real business.

Interim Sustainability Roles for Candidates

If you are an experienced sustainability executive looking for interim CSO, interim head of sustainability or fractional roles, please register with Exec Capital and browse our current opportunities. We are particularly interested in interims with UK SRS, ISSB or CSRD reporting experience, transition plan delivery and sector depth in manufacturing, energy, financial services, real estate or consumer businesses.

Frequently asked questions

What is an interim Chief Sustainability Officer?

An interim Chief Sustainability Officer is a senior sustainability executive engaged for a fixed term, usually full-time, to lead the sustainability function, deliver a specific programme or cover a gap before a permanent appointment. CSO here means Chief Sustainability Officer, not Chief Strategy Officer.

What is the difference between an interim CSO and an interim head of sustainability?

Mainly level and authority. An interim CSO sits on or reports directly to the executive committee and owns strategy and board reporting. An interim head of sustainability or Sustainability Director usually leads delivery one level below. We run both searches and help you decide which title fits the brief.

How quickly can an interim CSO start?

Interims are generally available sooner than permanent candidates, but it depends on the profile and whether candidates are finishing other assignments. We confirm realistic start dates at briefing and agree the search timetable with you then.

How long do interim CSO assignments last?

Most run for six to twelve months, often with an extension where a reporting cycle or transaction runs on. The term and notice period are set out in the contract.

How much does an interim Chief Sustainability Officer cost?

Interim CSOs are paid a day rate that reflects the scope, complexity, sector and urgency of the role. When you engage through Exec Capital the day rate includes our fee. We give current market guidance at briefing and confirm each candidate’s rate in writing.

Do we need a CSO for the UK Sustainability Reporting Standards?

There is no legal requirement to appoint a CSO. But listed issuers will report against UK SRS on a comply-or-explain basis under FCA PS26/19 for periods starting on or after 1 January 2027, and someone senior has to own that work with the CFO. Many listed companies use an interim to deliver the first report.

Does CSRD still apply to UK companies?

Far fewer UK businesses are affected since the EU Omnibus changes. UK groups are generally caught at group level only with more than €450 million of EU turnover, from financial year 2028, although EU subsidiaries meeting the EU thresholds may have their own obligations. Take advice on your own position.

Should we use an interim CSO or an ESG consultancy?

A consultancy is good for specialist technical work and defined projects. An interim CSO sits inside your leadership team, takes decisions and builds internal capability. Many businesses use both, with the interim directing the consultants.

Is an interim CSO inside or outside IR35?

It depends on the working arrangements. For medium and large clients the client makes the status determination. We discuss the likely position at briefing and can engage interims on either basis.

Can an interim CSO become permanent?

Yes, and it happens. If you want that option, tell us at the start so conversion terms are set out in the contract. Otherwise we can run the permanent search in parallel through our CSO recruitment service.

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