Short answer
The answer, before the reasoning
UK SRS S1 is closely based on IFRS S1, but it is not identical. The UK amendments change implementation in six important areas: reference to SASB Standards is optional rather than mandatory; the IFRS effective date is removed; the first-year relief allowing delayed publication after the financial statements is removed; the climate-only provision is no longer limited by the standard to the first reporting year; use of that provision prevents a UK SRS S1 compliance claim; and UK law or regulation can override the availability or operation of transition and compliance provisions.
A report can support both UK SRS S1 and IFRS S1 claims only after the entity tests each difference separately. UK compliance by itself is not evidence of IFRS compliance, and IFRS compliance by itself is not evidence of UK compliance. UK SRS S1 and IFRS S1 dual-compliance matrix · London Reporting Academy educational visual
Why the standards should not be called identical
The main disclosure architecture is substantially aligned. Both standards use the same investor-focused objective, materiality concept, reporting entity, four pillars, connected-information requirements, sources-of-guidance architecture, timing, comparatives, judgements, uncertainty and error principles.
However, a small number of amendments can change the reporting timetable, source process and compliance statement. These are not editorial differences. They affect whether a report can make an explicit and unreserved claim and whether a first-year implementation plan is valid.
The UK standard also states that UK Sustainability Reporting Standards are issued by the Secretary of State for Business and Trade for application in the UK and have not been prepared or endorsed by the ISSB. A UK SRS statement should therefore not be described as an IFRS Foundation or ISSB compliance statement unless the entity has completed the separate IFRS test.
In practice
Comparison at a glance
| Issue | IFRS S1 | UK SRS S1 — Implementation consequence |
|---|---|---|
| SASB disclosure topics and metrics | Entity shall refer to and consider applicability in the relevant source process. | Entity may refer to and consider applicability. — A UK-only report can use another defensible industry source process; an IFRS claim still needs evidence of the mandatory SASB consideration. |
| Standard-set effective date | Annual periods beginning on or after 1 January 2024; earlier application permitted with IFRS S2. | No standard-set effective date. Voluntary entities can choose when to apply, subject to UK law or regulation. — Record a UK first-application date and a separate IFRS application date. |
| Same-time application with S2 | Required. | Required. — Both bases require S1 and S2 together, subject to climate-first or climate-only provisions. |
| First-year delayed publication | IFRS E4 permits specified later publication in the first year. | Removed. Paragraph 64 requires publication at the same time as related financial statements. — A report published later may satisfy IFRS E4 but fail UK SRS S1. |
| Climate-only provision | IFRS E5 is available in the first annual reporting period. | UK E3 removes the first-year limit; availability can be set by UK law or regulation. — Voluntary UK phasing can continue longer, but an IFRS claim cannot use the relief beyond the first IFRS year. |
| Compliance while climate-only | IFRS educational material confirms first-year climate-first reporting can still support IFRS compliance when all applicable requirements are met. | UK paragraph 73A prohibits a UK SRS S1 compliance claim when E3 is used. — The same climate-only report can have different UK and IFRS claim outcomes. |
| Local regulatory overlay | Jurisdictional adoption can set local requirements, but IFRS S1 itself does not contain the UK-specific paragraphs. | Paragraphs 73B and E5 make application subject to Companies Act, FCA or other competent UK rules. — Regulatory compliance and standard-level compliance must be assessed separately. |
Difference 1 - SASB optionality
IFRS S1 requires an entity, when applying the relevant sources-of-guidance paragraphs, to refer to and consider the applicability of SASB disclosure topics and metrics. The entity may conclude that a particular SASB item is not applicable, but the consideration process is required.
UK SRS S1 changes “shall” to “may” in paragraphs 55(a) and 58(a). A UK reporter is not required by those paragraphs to perform the specific SASB consideration step.
This does not remove the need for industry-relevant information. The entity still has to identify material risks and opportunities and, where no dedicated UK standard exists, apply judgement to provide relevant and faithfully representative information. It must disclose the standards, pronouncements, industry practices and other sources of guidance actually applied.
Dual-claim control
For a dual UK and IFRS claim, keep a SASB consideration record even if the UK methodology uses UK regulation, peer practice, CDSB materials, ESRS, GRI, TNFD or entity-specific metrics. The record should show:
the applicable SASB industry or industries considered;
relevant disclosure topics and metrics reviewed;
items selected, adapted or rejected;
reasons for non-applicability;
alternative sources used; and
reviewer approval.
A statement that “SASB is optional in the UK” does not evidence the IFRS process requirement.
Difference 2 - effective date and initial application
IFRS S1 is effective for annual reporting periods beginning on or after 1 January 2024, with earlier application permitted when IFRS S2 is applied at the same time.
UK SRS S1 removes the standard-set effective date. A voluntary user can choose the reporting period from which it applies the standard. If UK law or regulation later requires application, the relevant authority can specify the commencement period.
The absence of a UK effective date does not mean that the entity can leave the first-application decision informal. It should document:
the first annual period for UK SRS S1;
whether the report is voluntary or required;
the first annual period for any IFRS S1 claim;
whether the periods differ;
which transition provisions are available under each basis; and
any local rule that restricts or replaces a standard relief.
A group may therefore have a UK SRS first-application year that differs from the parent group's IFRS S1 first-application year. The reporting file must preserve both clocks.
Difference 3 - first-year publication timing
IFRS S1 paragraph E4 permits an entity in its first year to report sustainability-related financial disclosures after publication of the related financial statements, subject to specified deadlines linked to interim reporting or a nine-month limit.
The UK government removed this relief from UK SRS S1. Paragraph 64 requires the sustainability-related financial disclosures to be reported at the same time as the related financial statements and to cover the same reporting period.
This difference changes project design. A first-time UK reporter cannot plan to finalise the sustainability report months after the annual report while still claiming UK SRS S1 compliance. Finance, sustainability, risk, legal, data and board approval must be integrated into the annual-report close.
Dual-claim consequence
A first-year report published within the IFRS E4 window might support an IFRS claim, but it would ordinarily fail UK paragraph 64. A combined claim should therefore use the stricter same-time UK timetable unless another applicable UK rule expressly changes the position.
Difference 4 - climate-only relief duration
IFRS S1 paragraph E5 permits climate-first reporting only in the first annual reporting period in which IFRS S1 is applied. The entity applies IFRS S1 insofar as it supports disclosure of climate-related risks and opportunities under IFRS S2 and discloses use of the relief.
UK SRS S1 paragraph E3 uses the same climate-only concept but removes the first-year limitation. Paragraph E5 makes its availability subject to UK law or regulation where application is mandatory.
For a voluntary UK reporter, the text therefore permits climate-only reporting beyond one year unless a relevant UK rule limits the relief. For the proposed FCA route, CP26/5 suggested a two-year non-climate deferral for the first cohort. That is a proposal, not the default duration for every user.
First IFRS year: the entity may be eligible for both the IFRS climate-first relief and the UK climate-only provision.
Second or later IFRS year: the IFRS relief is no longer available, even if the UK entity continues to use E3 voluntarily or under a UK regulatory phase-in.
A UK-only climate report after the first year should not imply IFRS S1 compliance.
Difference 5 - compliance statement while using climate-only reporting
This is the most significant claim difference.
Official IFRS educational material explains that a company using the IFRS S1 first-year climate-first transition relief can still assert compliance with IFRS S1 and IFRS S2 if it applies all requirements that are applicable under the relief.
UK SRS S1 paragraph 73A takes a different approach. An entity using paragraph E3:
is not permitted to assert compliance with UK SRS S1; and
must disclose use of the provision.
The entity is not automatically prevented from asserting UK SRS S2 compliance, provided the relevant S1 foundations, S2 requirements and relief disclosures are satisfied.
Example claim outcomes
The compliance statement should be drafted only after the technical team has classified every relief and unresolved gap.
In practice
| Reporting approach | UK SRS S1 claim | IFRS S1 claim |
|---|---|---|
| Full S1/S2 reporting with all requirements met | Possible. | Possible, subject to IFRS-specific differences. |
| Climate-only in first UK and first IFRS year | Not permitted under UK 73A. | Potentially possible under IFRS E5 if all applicable requirements are met and use is disclosed. |
| Climate-only after first IFRS year | Not permitted under UK 73A. | Not available as an IFRS S1 compliance route. |
| Partial S1-aligned report without E3 basis | Not permitted. | Not permitted. |
Difference 6 - UK regulatory override
UK SRS S1 paragraphs 73B and E5 recognise that Companies Act, FCA or another competent UK authority can determine how the standard applies when reporting is mandatory. This can affect:
the availability and duration of the climate-only provision;
the compliance basis;
report location;
explanation requirements;
transition timing; and
interaction with other statutory disclosures.
A company may therefore comply with a local comply-or-explain rule without being able to make a complete UK SRS S1 statement. Conversely, a voluntary report might meet the standard but still fail a separate statutory location or filing requirement.
The dual-reporting file should include three columns, not two:
1. UK SRS S1 requirements;
2. IFRS S1 requirements; and
3. applicable UK legal or regulatory overlay.
Comparative-information differences after climate-only reporting
Both standards relieve first-time reporters from comparative information in the first annual reporting period. Both also address the later introduction of wider sustainability reporting after climate-first reporting.
UK SRS S1 paragraph E4(b) links the wider-sustainability comparative relief to the second annual reporting period in which the entity ceases using E3. This accommodates a UK climate-only period that may last longer than one year.
The reporting calendar should therefore show, by topic:
first year of climate disclosure;
first year of wider sustainability disclosure;
first year in which climate comparatives are required; and
first year in which non-climate comparatives are required.
Do not assume that one “year one” flag applies to every metric and narrative disclosure.
In practice
Dual-compliance decision matrix
| Test | UK SRS S1 question | IFRS S1 question — Evidence needed |
|---|---|---|
| Reporting period | What is the chosen or required first UK period? | What is the IFRS initial application period? — Basis paper and period register. |
| S2 application | Has UK SRS S2 been applied at the same time? | Has IFRS S2 been applied at the same time? — Standards matrix and climate report. |
| SASB | Was any UK source process defensible and disclosed? | Was SASB referred to and considered? — Source-of-guidance decision log. |
| Timing | Were disclosures published with financial statements? | If later, was IFRS E4 eligibility satisfied? — Publication calendar and authorisation record. |
| Climate-only | Was UK E3 used and disclosed? | Was IFRS E5 used only in the first IFRS year and disclosed? — Relief register. |
| Comparatives | Were UK E1/E4 requirements applied by topic? | Were IFRS E3/E6 requirements applied? — Comparative matrix. |
| Compliance claim | Does UK paragraph 72 permit the claim, considering 73A/73B? | Does IFRS paragraph 72 permit the claim? — Separate claim memoranda and approvals. |
| Local rule | Does the FCA, Companies Act or another rule alter application? | Does the local overlay still permit an IFRS claim? — Legal applicability paper. |
Hypothetical dual reporter
A UK parent applies UK SRS voluntarily for 2027 and its international investors ask for an IFRS S1 and S2 compliance statement. The company plans climate-only reporting in 2027 and wants to publish the sustainability report six months after the financial statements.
The proposal creates two claim conflicts:
1. UK SRS S1 paragraph 73A prevents a UK SRS S1 claim while E3 is used; and
2. UK paragraph 64 does not contain the IFRS first-year delayed-publication relief.
The company could redesign the plan by publishing the climate disclosures with the financial statements. It might then be able to make an IFRS S1/S2 first-year climate-first claim if all applicable IFRS requirements are met. It still could not make a UK SRS S1 claim, although it could assess a UK SRS S2 claim with the required disclosure of relief use.
In the following year, a full IFRS S1 claim would require expansion beyond climate. Continuing climate-only reporting under UK E3 would not extend the IFRS transition relief.
This example is illustrative and requires entity-specific legal and technical review.
In practice
Common comparison errors
| Error | Why it is wrong | Control |
|---|---|---|
| “UK SRS S1 is IFRS S1 with a UK label.” | Source obligations, timing relief, climate-only duration and claims differ. | Maintain a paragraph-level difference register. |
| “SASB is optional, so industry analysis is optional.” | UK SRS still requires relevant and faithfully representative information and disclosure of sources used. | Document alternative sources and industry rationale. |
| “First-year IFRS timing relief works for UK SRS.” | The relief was removed from UK SRS S1. | Use the same-time UK timetable for a dual claim. |
| “Climate-only reporting can claim both standards.” | UK 73A prevents the UK S1 claim, while IFRS eligibility is first-year only. | Approve separate claim wording. |
| “A local comply-or-explain report is UK SRS compliant.” | Regulatory compliance and standard compliance are different tests. | Reconcile the final legal rule with paragraph 72. |
| “One first-application date is enough.” | UK, IFRS and local-rule commencement dates may differ. | Maintain a multi-basis transition calendar. |
Readiness
Technical reviewer checklist
- Exact UK SRS S1 and IFRS S1 editions are recorded.
- UK and IFRS first-application dates are separately documented.
- The SASB consideration requirement has been tested for the IFRS claim.
- Publication timing meets UK paragraph 64.
- Climate-only eligibility and duration have been tested under both bases.
- UK paragraph 73A claim restriction is reflected in wording.
- Comparative relief is tracked separately for climate and non-climate information.
- Companies Act, FCA or other UK overlay has been assessed.
- UK and IFRS compliance statements have separate approval memoranda.
Sources
Primary sources
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