TL;DR: UK discrimination law has nine protected characteristics and four types of discrimination, no 80% threshold, and no cap on compensation. This guide shows HR how to classify a complaint correctly, what a claim really costs, and which prevention steps to document before 30 October 2026.
Why getting the label right matters before anything goes wrong
A grievance lands on a Tuesday afternoon. Before you decide who investigates it, before you open the handbook, you make a quieter decision: what kind of complaint this is. That one choice sets the legal test, and with it the size of the exposure.
Live disputes rarely arrive looking like the examples in a training deck. They arrive as a comment nobody wrote down, a rule that has sat in the handbook for years, or a shift pattern that suits most of the team. Filing one of those as "a conduct issue" is how a manageable problem becomes an uncapped one.
This piece covers four things. The nine protected characteristics, including the ones HR routinely reads wrongly. The four types of discrimination, organised by the trigger that actually produces each one. Why the 80% rule is not UK law. And what a claim costs an employer when prevention fails.
It is a reference for employers rather than legal advice. Anything borderline goes to an employment lawyer before you act on it.
The nine protected characteristics, and the ones HR reads wrongly
Section 4 of the Equality Act 2010 lists nine. In workplace terms:
- Age. A job advert asking for a "recent graduate".
- Disability. Turning down a request for screen-reading software from an employee with deteriorating sight.
- Gender reassignment. Refusing time off for gender-reassignment medical appointments.
- Marriage and civil partnership. Dropping a married employee from a secondment list on an assumption that a spouse makes relocation difficult.
- Pregnancy and maternity. Marking someone down in an appraisal for pregnancy-related absence.
- Race. A grooming standard written without any thought for hair types other than one.
- Religion or belief. An all-staff social built entirely around alcohol.
- Sex. A rota where the better-paid overtime consistently goes to the men on the team.
- Sexual orientation. A manager who keeps making jokes about a colleague's partner.
Disability has a statutory test and it is worth knowing in full, because managers tend to apply their own. It is a physical or mental impairment with a substantial and long-term adverse effect on the person's ability to carry out normal day-to-day activities. "Substantial" means more than minor or trivial, which is a lower bar than the word suggests. "Long-term" means it has lasted or is likely to last at least 12 months, with separate rules for conditions that recur. The EHRC guidance on disability discrimination sets out how the test is applied.
Two of the nine do not behave like the rest.
Marriage and civil partnership is narrower than most HR teams assume. It protects people because they are married or in a civil partnership. It is not a general protection for relationship status, so single employees and unmarried couples living together are not covered by this characteristic.
Gender reassignment, under section 7 of the Act, covers someone who is proposing to undergo, is undergoing, or has undergone a process to reassign their sex. No medical treatment is required for the protection to apply, and neither is a Gender Recognition Certificate. An employee who has told you they intend to transition is already protected.
Pregnancy and maternity uses a different test altogether. Section 18 asks whether the woman was treated unfavourably during the protected period, which runs from the start of the pregnancy to the end of her maternity leave. There is no comparator. You do not ask how a man or a non-pregnant colleague would have been treated, which removes the argument employers most often reach for.
One more point the list-style guides miss. An employee can hold several characteristics at once, and a single decision about an older disabled worker can be challenged on age and disability together, on different tests, in the same claim.
Direct, indirect, harassment, victimisation: triaging the complaint on your desk
Four types, four different tests. The useful way to learn them is by the situation that produces each one rather than by the definition.
Direct discrimination is less favourable treatment because of a protected characteristic. The trigger is usually a decision or a remark you can trace to one person. A manager who stops advancing a candidate after she mentions a disability at interview is the standard shape, and it is the type most managers can already recognise.
Indirect discrimination is a rule that applies to everyone but puts people who share a characteristic at a particular disadvantage. In the statute it is a "provision, criterion or practice" under section 19, and it is only unlawful if the employer cannot objectively justify it. The trigger here is almost never a rogue manager. It is a rule nobody thought was controversial: compulsory Saturday shifts, a role advertised as full-time only, or a job spec demanding ten years in the sector. ACAS has a plain explanation of the test. This is the type HR misses most often, because the paperwork looks even-handed.
Harassment is unwanted conduct related to a characteristic that violates someone's dignity, or creates an environment that is intimidating, hostile, degrading, humiliating or offensive for them. The trigger is usually conduct the perpetrator describes as banter. Intent is not the test, so "he didn't mean anything by it" answers a question nobody asked.
Victimisation is a detriment imposed on someone because they did a protected act, such as raising a complaint or giving evidence in someone else's. The trigger is what happens in the weeks after a grievance: a promotion quietly withdrawn, an invitation to meetings that stops arriving, a performance review that materialises for the first time in three years.
Victimisation deserves its own warning. It is the type the employer creates, after the original complaint, through the behaviour of people who feel accused. It stands on its own even where the original allegation fails entirely, and where the treatment is bad enough to push someone out it brings constructive dismissal risk with it.
At triage stage, do not force a single label. The same facts regularly support two classifications, and narrowing too early shapes an investigation around the wrong question.
The 80% rule: an American screening tool, not UK law
There is no 80% rule in UK discrimination law. There is no four-fifths rule either. The phrase has travelled into UK HR conversations and it does not belong there.
It comes from the US Uniform Guidelines on Employee Selection Procedures, published in 1978, where the EEOC treats a selection rate below four-fifths of the highest group's rate as a flag worth investigating. Even in the US it was never a legal definition of discrimination, only an internal enforcement trigger, as the EEOC's own questions and answers set out. American courts have questioned its statistical validity since the 1980s, because small applicant pools produce noisy ratios and the cutoff itself is arbitrary.
Search the Equality Act 2010 for it and you will not find it. It is not in ACAS guidance and it is not in EHRC guidance.
What governs the question instead is the section 19 test: particular disadvantage, then objective justification, with no numeric threshold anywhere in it. A policy with a 90% ratio can still be unlawful. A policy at 70% can be lawful if the employer justifies it.
Justification is where employers actually lose, so be precise about it. The practice must be a proportionate means of achieving a legitimate aim, which means showing that no less discriminatory alternative was available. Cost on its own is not enough. The same reasoning applies when the selection is made by software rather than a person, which is why how the Equality Act applies to algorithmic hiring tools matters to anyone buying a screening product.
Selection-rate data still has a use. It tells you where to look. It is never a defence and never a safe harbour.
What a discrimination claim actually costs an employer
Discrimination compensation is uncapped. An ordinary unfair dismissal award runs into a statutory limit; a discrimination award does not.
The mechanism is worth understanding because it is often described loosely. There is no clause announcing that awards are unlimited. Section 124 sets out the tribunal's remedies and simply specifies no ceiling, so the claimant's full financial loss is recoverable, including lost earnings, pension loss and interest.
Sitting on top of that is a separate discretionary award for injury to feelings, set by the bands established in Vento v Chief Constable of West Yorkshire Police in 2002 and uprated each April by Presidential Guidance. For claims presented on or after 6 April 2026, the Ninth Addendum sets the lower band at £1,300 to £12,600 for one-off or less serious incidents, the middle band at £12,600 to £37,700 for serious cases that do not merit the top band, and the upper band at £37,700 to £62,900 for the most serious, such as a prolonged campaign of harassment. Exceptional cases can go above £62,900. Because the bands move every April, check the current addendum rather than a figure you remember.
On the scale of real awards, 2023/24 is the most recent published year. Ministry of Justice tribunal statistics for that year, as reported by Lexology, put the average sex discrimination award at £53,403, up from £37,607 the year before, race discrimination at £29,532, up from £23,070, and disability discrimination at £44,483.
The averages alone mislead, in both directions. The median disability award that year was £17,218 against that mean of £44,483, so most awards were moderate and a small number were very large. The largest single discrimination award reported for 2023/24 was £995,128, in a sex discrimination case, and age discrimination produced the highest average of any jurisdiction at around £100,000. A finance director who dismisses tribunal exposure as tail risk is answered better by the median than by the million.
There is also a clock. A claim must reach ACAS for Early Conciliation within three months less one day of the act complained of, or of the last act in a continuing course of conduct, with the limitation period paused while conciliation runs. ACAS explains how that works. As background, claim volumes have been rising sharply: around 11,857 single claims were filed between January and March 2026, reported as up roughly 58% year on year, with disability discrimination claims reported as up around 99% in the preceding quarter.
The standard rises on 30 October 2026
Since 26 October 2024, employers have had a duty to take reasonable steps to prevent sexual harassment of their workers, including harassment by third parties such as clients, customers and contractors.
From 30 October 2026, the Employment Rights Act 2025 raises that to all reasonable steps, matching the wording of the existing statutory defence in section 109(4).
One word changes the question a tribunal asks. Under the current duty, the enquiry is whether what the employer did was reasonable. Under the new one, it is whether there was anything further the employer could reasonably have done. An employer who delivered training, and nothing else, has a thinner answer to the second question than to the first. Third-party harassment liability is also extended expressly where the employer failed to take all reasonable steps to prevent it. CMS and Littler have both published detail on the October package.
The honest complication is that regulations setting out what counts as a reasonable step are not expected until 2027/28. The standard arrives before its boundaries, which will be filled in by guidance and early tribunal decisions.
That leaves one practical instruction for the gap. Write down the steps you take and the reasoning behind each one, at the time you take it. A step you cannot evidence two years later is a step you did not take.
A prevention checklist you can work through this quarter
- Policy wording. One equality and anti-harassment policy that names all nine characteristics, refers to the EHRC Employment Statutory Code of Practice, covers third parties, and states plainly that intent is not the test for harassment.
- Risk assessment. Record where harassment risk actually sits in your business, by site and working pattern. The all reasonable steps standard assumes you looked before anything happened.
- Manager training. The classification triage above is the syllabus. Most managers can spot direct discrimination, miss indirect discrimination completely, and almost none recognise victimisation in their own behaviour after a grievance.
- Reporting routes. At least two, and never only the line manager, because the line manager is the most common subject of the complaint.
- Decision audit. Review recruitment criteria, shift patterns, attendance triggers and redundancy selection for rules that disadvantage one group without a justification you would be willing to put in writing. Building selection criteria you could defend in a tribunal is the same exercise applied to redundancy.
- Monitoring. Track selection and outcome rates by characteristic, and treat the result as a pointer to where you should look rather than as a score you passed.
- Record keeping. Dated records of training delivered, policy acknowledgements, risk assessments and how each grievance was handled.
- Escalation discipline. Decide now which categories of complaint go straight to an employment lawyer instead of being handled informally by whoever picked up the email.
What to do with this
Three things are worth keeping. Nine characteristics, two of which do not work like the other seven. Four types, each with a different test and a different everyday trigger. And no percentage threshold anywhere in UK law.
The 80% rule is the one to actively unlearn, because acting on it gives comfort about a policy that may still be unlawful.
Uncapped compensation is the figure that justifies prevention spend, and the published medians make that case more credibly than the worst case does.
Most of this is a documentation and training problem before it is a legal one, and a policy nobody can find answers nothing. That is the gap Aura is built for: employees ask a question in their own words and get an answer grounded in their employer's policy and local labour law, with anything needing judgment passed to the HR team.