What counts as relevant Scope 3 for a 2027 NHS Carbon Reduction Plan?

From April 2027, NHS suppliers on contracts worth £5 million or more a year (including VAT), plus new frameworks and dynamic markets, will need to report all relevant Scope 3 emissions in their Carbon Reduction Plan (CRP). That's a big step up from the five Scope 3 categories required under the 2024 CRP.

For who's in scope and what else changes, see our main guide to the NHS Net Zero Supplier Roadmap and what changes from April 2027.

But what counts as relevant?

The NHS doesn't set its own rules here. It defers to the GHG Protocol, which gives a framework for judgement rather than a fixed list.

The NHS defers to the GHG Protocol

The 2027 NHS CRP guidance asks suppliers to report emissions for all Scope 3 categories "deemed relevant", in line with the GHG Protocol Corporate Value Chain (Scope 3) Standard. For any category deemed not relevant, it says an explanation aligned to the standard must be provided.

So the test for relevance comes from the GHG Protocol, not the NHS.

Relevance is one of five principles that underpin carbon accounting under the GHG Protocol, alongside completeness, consistency, transparency and accuracy. Its aim is to make sure a footprint reflects the company's emissions and is useful to the people relying on it, both inside and outside the business.

The NHS also confirms that estimation methods, such as spend-based calculations using conversion factors, can be used for Scope 3.

Every category needs an answer

The Scope 3 Standard requires companies to account for all Scope 3 emissions and to disclose and justify any exclusions. In practice, each of the 15 categories ends up in one of three places:

Included: calculated and reported in the CRP.
Not applicable: the activity doesn't happen in the business at all, such as franchises for a company that has none.
Deemed not relevant: the activity happens, but has been judged not relevant against the standard's criteria, with a justification.

The standard adds that companies shouldn't exclude anything that would compromise the relevance of the inventory, in particular activities expected to contribute significantly to total Scope 3 emissions.

Start with a rough estimate of every category

The GHG Protocol recommends screening all Scope 3 activities with an initial estimate before deciding what's relevant. It's guidance rather than a requirement, but it's hard to judge the size criterion without it.

The estimate can be rough. The GHG Protocol suggests industry-average data, environmentally-extended input-output (spend-based) data, proxies or simple estimates, then ranking every activity from largest to smallest.

It also gives you evidence: a category deemed not relevant is far easier to justify with a number behind it.

The six criteria

Table 6.1 of the Scope 3 Standard sets out six criteria for deciding relevance, plus a seventh, open-ended "other".

Criterion

A category is likely relevant if…

Size

It contributes significantly to your total expected Scope 3 emissions. This is the one the screening estimate informs.

Influence

There are reductions you could make or encourage, for example through procurement policy, supplier engagement, product design or travel policy.

Risk

It adds to your exposure, whether through regulation, supply chain costs, falling demand for higher-carbon products, litigation or reputation.

Stakeholders

Key customers, suppliers, investors or civil society consider it critical.

Outsourcing

It’s work you used to do in-house, or that others in your sector usually do in-house.

Sector guidance

Guidance for your sector identifies it as significant.

Other

It meets any further criteria set by you or your sector.

A small category can still be relevant. A low estimate doesn't settle it if, say, a major customer asks about it or it's an obvious place to cut emissions.

Recording the justification

It's a loose framework. The standard doesn't say how many criteria a category needs to meet, so it comes down to judgement. So it's important to record how each decision was reached.

For anything deemed not relevant, record a detailed justification against each of the criteria. A simple register per category might hold:

the screening estimate and the data behind it
how the category measures up against each criterion
the decision, and the reasoning in a sentence or two
who made it, and when it'll next be reviewed

It's worth keeping "not relevant" separate from "relevant but not yet measured". The NHS guidance allows suppliers with Scope 3 data gaps in 2027/28 tenders to pass if they give an acceptable explanation and a plan to report the following year.

Relevance isn't the same as materiality

Relevance is sometimes confused with materiality, as in a materiality assessment. That's a separate exercise used in sustainability and ESG reporting to decide which topics a business reports on, such as climate, water or workforce. It doesn't decide which Scope 3 categories go in a footprint.

Looking ahead

The GHG Protocol has proposed that at least 95% of required Scope 3 emissions are reported, with exclusions capped at 5%. “Required” emissions are those within the minimum boundary set for each category in Table 5.4 of the Scope 3 Standard. For business travel, for example, that’s the fuel burned by the airline or train operator, while emissions from building the vehicles are optional. Draft wording also has companies quantifying total required Scope 3 emissions to justify exclusions, which would make the screening estimate a requirement rather than a recommendation.

This is still a draft, with consultation due in 2027. For now, the test for an NHS CRP is the current Scope 3 Standard and its relevance criteria.

Frequently Asked Questions

Which Scope 3 categories do NHS suppliers need to report from April 2027?

It depends on the contract. For contracts of £5 million a year or more (including VAT), and new NHS frameworks and dynamic markets, suppliers need to report all Scope 3 categories deemed relevant, using the GHG Protocol Scope 3 Standard to determine relevance. Contracts below £5 million stay on the 2024 CRP, which requires five set Scope 3 categories.

Do I need to report all 15 Scope 3 categories?

No. Under the 2027 NHS CRP, you need to assess all 15, report the ones that are relevant to your business, and give an explanation for any you deem not relevant.

Is there a percentage threshold for excluding Scope 3 categories?

Not in the current Scope 3 Standard. The GHG Protocol has proposed that at least 95% of required Scope 3 emissions are reported, with exclusions capped at 5%, but this is still a draft.

Can I use spend-based data for my 2027 NHS CRP?

Yes. The NHS guidance confirms that estimation methods, such as spend-based calculations using conversion factors, can be used for Scope 3.

What if I can't get data for a relevant category in time?

In NHS 2027/28 tenders, suppliers with gaps in their Scope 3 data can still pass if they give an acceptable explanation and a plan to report on those emissions from the following year. Remedying that gap will become part of your contract. This is different from deeming a category not relevant.