A query about a single-sex space — a toilet, a changing room, a ward, a refuge bed, a support group — is one of the few trans-inclusion questions that lands on a manager’s desk with no comfortable “wait and see” option. Someone is standing in a corridor, or on the phone, and an answer is needed today. This article is not a ruling on what that answer should be, and it is not legal advice. Every real case turns on its own facts — the nature of the service, the alternatives available, the reasons put forward, and the people affected — and the law in this area is still actively developing. What follows is a decision framework: a repeatable, documented process a manager can use to reach an answer that is defensible on the day it is made, whatever a court, regulator or board later makes of the underlying legal question. Crucially, it starts from the right question. That question is not “must we exclude this person” but “how can we include or accommodate them” — with a single-sex restriction treated as a proportionate, evidenced, documented exception of last resort, not the default a manager reaches for because it feels safer, is administratively easier, or is being demanded by someone applying pressure. Defaulting to exclusion for any of those reasons produces the least defensible decision of all. Take specific legal advice before finalising any policy built on this framework, and before any individual decision with serious consequences for the people involved.
What “defensible” means here
Defensibility does not mean guessing correctly how a contested legal point will eventually be resolved. It means being able to show, afterwards, that the decision was reasoned, proportionate, consistent with how comparable cases have been handled, based on a lawful starting point, and reached by first working out how to include the person and restricting only where a restriction could be genuinely justified — not defensive exclusion improvised under pressure with nothing written down. A manager who can produce that trail is in a materially stronger position than one who happened to reach the “right” answer but cannot show how or why they got there. This framework builds that trail, step by step.
Step 1: Work out what kind of question you are actually facing
Not every facilities query is a single-sex-space question, and not every single-sex-space question sits in the same legal regime. Before anything else, work out which of two very different contexts you are in, because they are governed by different rules. If the space is provided to the public as a service — a ward, a refuge, a support group, or a toilet in a venue open to visitors — you are in the domain of the Equality Act 2010’s services provisions and the EHRC’s single-sex Code of Practice for services, public functions and associations. If instead the space is a workplace facility for staff — the staff toilets, the staff changing room, the depot washroom — you are in the employment domain, governed by the Equality Act’s employment provisions and by separate workplace and health-and-safety regulations (the Workplace (Health, Safety and Welfare) Regulations 1992, for example, are the long-established rule requiring separate-sex sanitary and changing facilities for workers) — not by the services single-sex exceptions in Schedule 3. Many organisations are both an employer and a service provider, so the same building can involve both regimes at once: the same toilet block can raise a services question for a visitor and an employment question for a member of staff. Establish — and write down — which regime the query in front of you actually falls under, and take advice on which applies if it is genuinely both. The steps that follow work through the services single-sex question; for staff facilities the same proportionality discipline is still good practice, but the governing law is the employment and workplace regime, not the services Code, so do not treat that Code as the authority for a decision about staff facilities.
Within the services context, then settle the next basic: is this service or space genuinely provided on a single-sex basis, or is it a mixed service that someone is assuming should operate differently? Schedule 3, Part 7 of the Equality Act 2010 sets out the circumstances in which single-sex or separate-sex provision can lawfully depart from the general rule against sex discrimination in services; current EHRC guidance frames mixed, open-to-all provision as the ordinary starting point, with single-sex provision as an exception that has to be justified, not assumed. If the space in question is already mixed, a different — generally simpler — set of considerations applies than if it has been deliberately established and run as single-sex. Get this distinction clear and written down too.
Step 2: Understand the lawful basis — and where the burden sits
If the space genuinely is single-sex, the question is not “can we exclude someone” in the abstract — it is whether the exception applies and is currently justified. Two points matter here, and both sit within an area of law that is still moving, so treat them as the current state of interpretation rather than a fixed rule to apply mechanically.
The Supreme Court’s 2025 judgment in For Women Scotland Ltd v The Scottish Ministers held that “sex” in the Equality Act 2010 means biological sex, and that a Gender Recognition Certificate does not change that for the Act’s purposes — including the single-sex exceptions. That is a settled holding of the UK’s highest court. What the judgment did not do is require anyone to exclude trans people: it clarified what “sex” means in the Act, not that a single-sex exception must be used. The exception is permissive, not mandatory — a power a provider may rely on where a restriction is justified, never a duty to restrict, and nothing in the judgment (or in the services-only EHRC Code) compels exclusion. What it does not do is settle any individual case: reliance on a single-sex exception still requires a proportionality assessment decided case by case — a requirement that follows from how Schedule 3 has always operated rather than from a fresh finding in this judgment — while the Court was clear that gender reassignment remains a fully protected characteristic under section 7 of the Act, independent of the sex definition.
Separately, where a genuine single-sex exception exists, the burden of justifying it sits with the provider, not with the person seeking access having to prove they should be excluded from it. Getting that burden-of-proof direction backwards is one of the most consequential errors a manager can make in this area.
No code is itself “the law”: the EHRC’s updated statutory Code of Practice on services is guidance a provider must have regard to, not a binding rule in its own right. The Equality Act and the developing case law are what bind, the understanding is evolving with each new case, and a manager’s duty to treat people with dignity and respect and to reach a proportionate, documented decision applies whichever version of the Code you are reading. The EHRC has revised its guidance to reflect the Supreme Court’s ruling; note too that parts of the earlier 2011 Code’s worked examples predate that judgment and need to be read alongside it, not in isolation — where guidance and case law appear to pull in different directions is exactly the kind of point to take specific legal advice on, rather than resolve yourself.
Step 3: Weigh proportionality — properly, and case by case
Assuming a genuine single-sex exception is engaged, the live question is whether excluding this person, in this case, is a proportionate way of achieving a legitimate aim. Frame it the right way round: the starting presumption is inclusion, and the burden is on justifying any departure from it — not on the person to earn their way in. Three reasons never carry that justification on their own: that the law is assumed to compel exclusion (it does not), that exclusion is administratively easier, or that someone is applying external pressure to exclude. A decision reached for any of those reasons is defensive exclusion, not a proportionate one, and it is the least defensible outcome available. This is a judgement, not a checklist, but the considerations current guidance consistently points to include: what alternative provision realistically exists, whether cost or convenience is the only reason being offered (guidance is consistent that cost alone is not sufficient justification on its own), and whether the outcome leaves the person able to use some appropriate provision, or none at all. The direction of current EHRC guidance is that leaving someone with no facility they can use at all is very unlikely to be treated as proportionate — but whether a specific alternative is adequate in a specific case remains a fact-sensitive question this framework cannot answer for you. What it can insist on is that the weighing happens visibly: written down, dated, and showing what was considered and rejected, not only what was decided.
Two further points belong here. First, do not try to resolve uncertainty by demanding documentary proof of someone’s sex — no single UK document reliably establishes this, and asking for one raises separate legal and data-protection risks outside this framework’s scope; take advice before adopting any verification approach. Second, keep the assessment specific to the space and situation in front of you — a decision made here should not be treated as a template quietly applied to every future query without being reopened on its own facts.
Step 4: Document, communicate, and know when to escalate
Write down what was asked, what was considered, who was consulted, what alternatives were explored, and what was decided and why — before communicating the outcome, not after. This record is the defensibility itself; without it, even a well-reasoned decision looks like improvisation if it is ever challenged. Communicate the decision clearly and consistently to everyone affected, and treat any case involving legal risk, media interest, safeguarding concerns, or a service used by the wider public as one to escalate to HR, legal advice, or a named senior lead before it is finalised — not something to resolve alone at the point of query. If your organisation has no named individual accountable for this area, escalating to whoever holds the nearest equivalent responsibility is still better than deciding it unsupported.
Keep the file open
A single-sex space decision is rarely a one-off. Revisit it when circumstances change — a new judgment, updated EHRC guidance, a repeat query, or simply the passage of time — and date the review just as the original decision was dated. Some adjacent context is worth naming honestly here: in the Beyond Compliance survey of 136 UK organisations, 46.3% report providing gender-neutral toilet facilities at all or most sites, 19.4% at some sites only, and 13.4% at none — figures describing organisations’ self-reported facility provision, not the quality of any single-sex-space decision behind it. No survey measures that directly. This framework exists because that gap is real, and — so far — unmeasured. Closing it is not a matter of holding a stronger opinion about the law; it is the discipline of a documented, proportionate, case-by-case process, revisited as the ground shifts beneath it.