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Intelligence Hub · Energy & Carbon Compliance

ESOS & SECR: the compliance engine room

Before UK SRS makes headlines, two workhorse regimes decide what most large UK organisations actually measure: ESOS energy audits and SECR annual disclosures. Phase 4 qualification is tested this December — and the 2026 SECR review has put reform on the table. This hub tracks both.

Updated 12 June 2026 · Independent analysis · SRS Report
≥95%
Of total energy consumption must be covered by ESOS Phase 4 assessments — up from 90% in Phase 3
EA guidance [2]
£50,000
Maximum fixed penalty for failing to undertake an ESOS assessment, plus daily penalties
SI 2014/1643 [1]
2 of 3
SECR test for large unquoted companies: £36m turnover, £18m balance sheet, 250 employees
SI 2018/1155 [3]
6 Apr 2025
Companies Act size thresholds rose ~50% — but SECR scope was preserved on the old thresholds
SI 2024/1303 [6]
Analysis

Why we cover these two regimes as one system

ESOS and SECR are usually treated as separate compliance chores owned by different teams — energy management on one side, financial reporting on the other. That framing is increasingly obsolete. ESOS, established by the 2014 Regulations[1], forces a four-yearly audit of where energy is actually consumed across buildings, transport and industrial processes[2]. SECR, created by the 2018 Regulations[3], forces an annual public disclosure of energy use and emissions in the directors’ report[5]. One generates the measurement infrastructure; the other publishes its outputs.

The arrival of UK SRS S2 completes the system: climate disclosures under the new standards demand exactly the energy and emissions data these two regimes already compel large organisations to produce[7]. The organisations handling this well are running one data pipeline with three outputs — ESOS notification, SECR disclosure, S2 metrics — rather than three projects. Our analysis across this hub starts from that premise.

The date that matters this year: 31 December 2026. Organisations near the ESOS thresholds — 250 employees, or €50m turnover with a €43m balance sheet — should know before year-end whether they qualify for Phase 4, because the 12-month evidence period must cover the qualification date[2].
Side by side

ESOS vs SECR vs UK SRS S2 — obligations compared

The three regimes at a glance (June 2026)
ESOS (Phase 4)SECRUK SRS S2
NatureEnergy audit & notificationAnnual public disclosureAnnual public disclosure (voluntary; FCA rules proposed)
Who250+ employees OR >€50m turnover and >€43m balance sheetQuoted companies; unquoted companies & LLPs meeting 2 of: £36m / £18m / 250Voluntary now; listed companies proposed from FY2027
CadenceEvery 4 years + annual action-plan updatesEvery financial yearEvery financial year
Deadline5 December 2027 (Phase 4)With annual report filingWith annual report (proposed)
RegulatorEnvironment AgencyConduct: FRC / Companies House filingFCA (listed); DBT policy
Penalty exposureUp to £50,000 fixed + £500/dayLate/defective filing consequences under Companies ActListing Rule enforcement (once made)
Coverage

Energy & carbon compliance analysis on SRS Report

New analysisESOS Phase 4: the 2027 deadline analysedQualification on 31 December 2026, the 95% coverage rule, action-plan progress reporting, and where Phase 3 went wrong.New analysisSECR thresholds: who reports, and the trap in the 2025 size upliftWhy companies that became “medium-sized” in April 2025 can still owe SECR disclosures — and what the 2026 review signals.ReferenceESOS compliance analysisThe scheme mechanics: routes to compliance, lead assessors, and notification.ReferenceSECR requirementsWhat in-scope companies must disclose: energy, emissions, intensity ratios and efficiency narrative.PrimerStreamlined Energy & Carbon Reporting explainedThe full SECR picture from the 2018 regulations to current practice.AnalysisESOS and carbon reportingTurning audit findings into reporting-grade carbon data.ReferenceCarbon reporting requirements in the UKEvery UK carbon-disclosure obligation in one map.SectorESOS in the energy sectorSector-specific qualification and audit questions.MarketEmissions compliance consultantsThe advisory market for ESOS, SECR and carbon compliance — what support actually costs.MarketCarbon compliance consultancyWhen to buy advice versus build in-house capability for energy and carbon regimes.
Common questions

ESOS & SECR — frequently asked questions

What is the difference between ESOS and SECR?

ESOS is an energy audit scheme: qualifying organisations must assess their energy use every four years and notify the Environment Agency — it is about identifying savings, not public disclosure. SECR is an annual disclosure regime: in-scope companies must publish energy use, emissions and an intensity ratio in their annual report filed at Companies House. Many large organisations are caught by both.

When is the ESOS Phase 4 deadline?

The compliance notification deadline is 5 December 2027. Whether an organisation qualifies is tested on 31 December 2026 — any UK undertaking with 250+ employees, or with turnover above €50m and a balance sheet above €43m, on that date is in scope for Phase 4.

Do the new 2025 company size thresholds change who reports under SECR?

No. The Companies Act size thresholds rose by around 50% for financial years beginning on or after 6 April 2025 (large: >£54m turnover, >£27m balance sheet), but SECR scope was deliberately preserved on the previous thresholds — £36m turnover, £18m balance sheet, 250 employees (two of three). Companies reclassified as medium-sized under the new thresholds can still owe SECR disclosures.

How do ESOS and SECR relate to UK SRS?

They are upstream data sources. ESOS audits generate energy-consumption data and savings opportunities; SECR processes generate audited annual energy and emissions figures. Both map directly onto the metrics UK SRS S2 requires. Organisations that treat ESOS Phase 4 and SECR as a data-infrastructure project, rather than isolated filings, are effectively pre-building their S2 disclosure capability.

For the standards this data ultimately feeds, see the UK SRS Intelligence Hub. For the broader disclosure landscape including TCFD and ESG frameworks, see ESG reporting requirements in the UK.

Sources & primary references
  1. The Energy Savings Opportunity Scheme Regulations 2014 (SI 2014/1643), as amended 2023 — legislation.gov.uk
  2. Comply with the Energy Savings Opportunity Scheme (ESOS) — official guidance — Environment Agency, GOV.UK · Phase 4: qualification 31 Dec 2026, compliance deadline 5 Dec 2027
  3. The Companies (Directors’ Report) and LLPs (Energy and Carbon Report) Regulations 2018 (SI 2018/1155) — legislation.gov.uk · The SECR regulations
  4. 2026 post-implementation review of the SECR Regulations 2018 — Department for Energy Security and Net Zero, GOV.UK
  5. Environmental Reporting Guidelines: including SECR guidance — GOV.UK
  6. The Companies (Accounts and Reports) (Amendment and Transitional Provision) Regulations 2024 — legislation.gov.uk · Company size thresholds raised ~50% for FY beginning on/after 6 April 2025; SECR scope preserved on prior thresholds
  7. UK Sustainability Reporting Standards (UK SRS S1 and S2) — Department for Business and Trade, GOV.UK · Published 25 February 2026