Scope 3 reporting: which UK rule applies to you

The three scopes come from the GHG Protocol Corporate Standard, a voluntary accounting standard, and the split is about control of the emitting source rather than size or importance.

On the Corporate Standard alone, Scope 3 is an optional reporting category; the later Scope 3 Standard is what makes all fifteen categories accountable for a company that adopts it.

Your reporting duty, by contrast, comes from UK law and FCA rules, which each draw their own line across the same boundary — which is why the table above has four rows.

The test is applied to the source, not the activity.

A car your company owns and fuels burns Scope 1 fuel, while the same journey in an employee’s own car sits in Scope 3, category 6, even where the company reimburses every litre.

A leased vehicle you operate falls in Scope 1 or 2; one you lease but do not operate, and whose emissions are not already counted, falls in category 8, upstream leased assets.

Electricity you buy is Scope 2, but the upstream emissions of producing the fuel that generated it, and the losses in getting it to you, sit in Scope 3 category 3 — usually the easiest material category to calculate, because the factors are published.

For most organisations Scope 3 is the larger part of the total, and for a bank or an asset manager, category 15 usually dominates it.

Start with Scope 1, 2 and 3 emissions if the first two boundaries are unsettled; the concept, with examples by category, is on Scope 3 emissions, and the standard itself on the GHG Protocol.

The screener beside this text works through the fifteen categories in the order the Standard lists them.

It asks only whether you have the activity at all, because that is the first decision every inventory makes.

A “yes” goes on the list to measure, a “no” goes on the list to report as not applicable with the reason, and “not sure” stays open — because ¶B32 needs an answer for each.

It says nothing about which categories are large: that needs your own spend and activity data.

If you tick the financial-activities box, it adds the category 15 provisions; if you tick the listing box, it adds the FCA’s relief and the words the annual report has to carry.

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“Scope 3 is not required under SECR” is true of quoted companies and false of large unquoted companies and LLPs.

The government’s own Environmental Reporting Guidelines use the word “mandatory” for one slice of it.

The statutory hook is narrower than the guidance: Schedule 7 Part 7A ¶20D(1)(b), inserted by SI 2018/1155, reaches emissions from activities for which the company is responsible involving “the consumption of fuel for the purposes of transport”.

The test is responsibility for buying the fuel, not ownership of the vehicle, which is why employee-owned and hire cars on business use are caught — including fuel reimbursed through mileage claims.

This is often called the grey fleet: vehicles your people drive on your business that your company does not own.

The GHG Protocol calls exactly these journeys Scope 3 category 6, business travel, in the phrase the guidance itself uses: “business travel in rental cars or employee-owned vehicles”.

The guidelines also say what falls outside the mandatory figure: rail, flights and taxis you do not operate, and subcontracted transport of goods, which may be reported separately as Scope 3.

So the accurate sentence is: Scope 3 is largely voluntary under SECR, except for this slice of category 6, which has applied to large unquoted companies and LLPs since SECR came into force on 1 April 2019.

The relief attaches to an accounting period, not to a calendar year, so the year it covers depends on when your year starts.

The date of initial application is the beginning of the first annual reporting period that begins on or after 1 January 2027 but before 1 January 2028 (PS26/19 ¶3.18).

A company with an April year end therefore takes its relief for the year that begins on 1 May 2027, and reports Scope 3 or explains for the year that begins on 1 May 2028.

The resolver beside this text applies the transitional table in UKLR TP 16 to your listing category and the month your year starts, and names the provision that governs each period.

Its arithmetic is ours, from the paragraphs it cites; the full calendar of first periods and first reports is on the UK SRS deadline.

Two different things are called compliance here, and they come from different documents.

The first is compliance with the listing rules, which a company achieves either by disclosing or by explaining.

The second is the statement of compliance with UK SRS S2 itself, which belongs to the standard.

UK SRS S1 ¶73A lets an entity using the Scope 3 relief still assert compliance with UK SRS S2, provided it discloses that it used the relief alongside the statement.

The climate-first relief in S1 is different: an entity using it may not assert compliance with UK SRS S1.

Explaining after the relief expires is a third case: the FCA’s draft Technical Note says an issuer cannot make “an explicit and unreserved statement of compliance” with a UK SRS standard if it explains that it has not met one or more of its requirements.

The practical consequence: a company that drifts from relief to explanation without building its inventory keeps its listing-rule compliance and loses its unqualified standard compliance statement.

The draft also says there is no separate requirement for a compliance statement under the listing rules — the statement is the standard’s, and the company chooses whether it can make it.

The GHG Protocol’s calculation guidance distinguishes primary data from specific activities in your value chain from secondary data such as industry averages, published databases and proxies.

The guidance supplies methods by category; the requirements stay in the Scope 3 Standard itself, so cite the Standard for a rule and the guidance for a method.

The Standard’s §7.3 judges data quality by its representativeness in technology, time and geography, and by completeness and reliability, and says to prioritise improving data where quality is low and emissions are high.

Spend-based estimates are permitted, but they measure money rather than molecules: a supplier that cuts its emissions while holding its prices shows no improvement in your figure.

The government’s 2026 conversion factors distinguish themselves from Defra’s spend-based multipliers, which it says can give “an initial assessment of a user’s full supply-chain emissions” where activity data is lacking — and asks users to report the methods used.

The practical move is not to lift every category by one tier, but to lift the two or three largest to supplier data and leave the rest honestly labelled.

Chapter 11 of the Scope 3 Standard asks, for each category, a description of the types and sources of data and their quality, and the percentage calculated using data from suppliers or other value-chain partners — the same idea UK SRS S2 ¶B56 expresses.

Category 1 is the largest category for most non-financial organisations and the one you control least.

The sequence that works is screen first, then spend: estimate every category cheaply, rank suppliers by estimated emissions rather than by spend alone, and ask the few that matter for something specific.

A vague request gets a vague answer; a request for a product carbon footprint in a named format, with a deadline, gets data you can use.

Expect refusals on confidentiality grounds, which the DESNZ evidence names as a barrier distinct from capability.

Keep the request in contracts once it works, so it recurs each year without being renegotiated.

Your own figures travel the other way too: a customer reporting under UK SRS, or a lender measuring financed emissions, will ask for your Scopes 1 and 2, which is often how a smaller company first meets Scope 3 at all.

No UK rule requires Scope 3 figures to be assured.

The made listing rule, UKLR 6.6.6R(8)(d), requires a statement of whether third-party assurance was obtained and, if it was, the provider, which disclosures were assured and to what level — reasonable or limited — the standards used, and where any published assurance report can be found.

The FCA says it is “not requiring explanations in the absence of assurance being sought”, so a company that obtained none says so and gives no reason.

ISSA (UK) 5000, issued by the FRC on 12 November 2025 for voluntary use, is effective for engagements on periods beginning on or after 15 December 2026, or as at a date on or after then, and earlier application is permitted; it is listed on the FRC’s assurance standards page.

Limited assurance ends in a negative-form conclusion — nothing has come to the practitioner’s attention — while reasonable assurance is a positive opinion and much more work.

The gap between a self-reported Scope 3 figure and an assurable one is almost always documentation rather than arithmetic, which is why the panel lists papers rather than calculations.

The wider picture is on sustainability assurance; the dates for the whole programme are on the family’s UK SRS timeline.

Each statement beside this text circulates in guides, board papers and vendor material.

Each is settled by the provision named under its answer, and the page above sets out the reasoning in full.

The second and the last are the expensive ones, because they tell a company it has a duty that the rules do not impose.

Nothing you choose is stored or sent.