Sustainability consultancy: the UK guide

A sustainability consultancy is a specialist advisory firm that helps an organisation measure, manage and disclose its environmental, social and governance performance.

The core deliverables are usually a greenhouse-gas footprint, a net zero or transition plan, a materiality assessment, and disclosures prepared against the frameworks that apply to the company1.

In the UK that increasingly means readiness for UK SRS, ongoing SECR reporting4, and — where assurance is required — engagement readiness under ISSA (UK) 50003.

The clearest trigger is entering a mandatory regime for the first time.

UK SRS S2 is proposed mandatory for around 500 listed companies from 1 January 2027 under FCA CP26/52, and many more companies face it indirectly through supply-chain and investor pressure.

Other common triggers are a first SECR filing, a customer or tender ESG questionnaire, a financing or M&A process, and preparing data so it can withstand third-party assurance3.

"Sustainability consultancy" is a broad label; in practice firms cluster around a few specialisms.

A net zero consultancy focuses on target-setting and decarbonisation — typically Science Based Targets and a transition plan.

A carbon consultancy focuses on measuring the footprint itself — Scope 1, 2 and 3 — plus SECR compliance and offsetting strategy.

Reporting and assurance advisers focus on the disclosure itself: materiality, the four-pillar structure of UK SRS S1 and UK SRS S2, and readiness for assurance1.

A CSRD consultancy advises on the EU Corporate Sustainability Reporting Directive and its ESRS standards, including the double-materiality assessment that distinguishes CSRD from the single-materiality approach of UK SRS.

UK groups with qualifying EU operations can fall within CSRD scope, so a UK company may run CSRD and UK SRS preparation in parallel; our UK SRS vs ESRS comparison sets out where the two diverge.

For the wider UK obligations a consultancy will scope, see our UK ESG reporting requirements guide.

The three routes are complementary rather than mutually exclusive.

Many UK companies adopt a hybrid: a consultancy for the first footprint and assurance readiness, sustainability software for the ongoing cycle, and a small in-house team to own the programme.

Match the firm to your trigger and framework rather than to the broadest brochure.

Check that they work to the standards you must report against — UK SRS, SECR, CSRD or TCFD — and that their carbon methodology follows the GHG Protocol with current DESNZ factors.

Ask for fixed-scope proposals from two or three firms, compare the deliverables, and confirm whether assurance readiness under ISSA (UK) 5000 is included3.