Can I dismiss someone for poor performance in the UK?

Yes, you can dismiss for poor performance — but not by "having a word" on Monday and sacking them on Friday because you're fed up.

With unfair dismissal making up a large chunk of tribunal claims and rising, a sloppy capability process is now an expensive hobby.

From January 2027, unfair dismissal protection kicks in after just six months' service and there will be no statutory cap on compensation under the unfair dismissal changes under the Employment Rights Act 2025. That means you have to take performance management seriously, even for relatively new hires.

When is dismissal for poor performance legally fair?

For most employees (ignoring automatically unfair reasons), a dismissal must be:

• For a potentially fair reason — capability/performance is one.
• Follow a fair procedure.
• Be within the "band of reasonable responses" for a reasonable employer.

Poor performance means they can't do the job to the required standard, even with reasonable support — not just that you don't personally like how they do it.

If you haven't given clear expectations, feedback and an opportunity to improve, it will be very hard to justify dismissal as fair.

Step 1 – Get clear on expectations and evidence

Before you even think about dismissal, you need to know:

• What "good" looks like for this role (targets, behaviours, outputs).
• How the employee is falling short (numbers, deadlines, errors, complaints).
• What you've already said or done about it, formally or informally.

If all you have is "everyone thinks they're a bit rubbish", you're not ready.

You need tangible examples that you could, in theory, put in front of a tribunal if you had to.

Step 2 – Have an informal performance conversation (properly)

In many cases, you can and should start informally. That doesn't mean a vague moan in passing; it means a structured chat that you happen not to call "disciplinary".

Cover:

• Specific examples of where they're underperforming.
• The standard you expect and by when.
• What support you'll give (training, shadowing, clearer targets).
• When you'll review progress.

Make a short note afterwards of what was said and agreed.

If performance improves and stays improved, great; if it doesn't, you've laid the groundwork for a formal process.

Step 3 – Formal performance management and capability procedure

If informal steps haven't worked, you move into a more formal capability process. This is where "how many warnings before dismissal?" actually has context.

A typical small-business process:

1. Invite to a formal performance meeting
   • Written invite, reasonable notice, right to be accompanied.
   • Share the performance concerns and evidence in advance.
2. First formal warning
   • Meeting to discuss performance, employee's explanation, any support needed.
   • Confirm in writing: what must improve, clear and measurable targets, support you'll provide, review period, and that continued underperformance may lead to further action, including dismissal.
3. Review period
   • Regular check-ins.
   • Record progress — good or bad.
4. Second formal warning (if needed)
   • If no or insufficient improvement, invite to another meeting.
   • Explain that further failure may result in dismissal.
   • Confirm in writing.
5. Final review and possible dismissal
   • If performance is still significantly below standard, invite to a final capability hearing.
   • Consider all evidence, support offered, and whether any adjustments were needed (e.g. disability).
   • If you dismiss, confirm dismissal with notice in writing, including right of appeal.

The exact number of warnings can vary, but going straight from nothing to dismissal is asking for trouble unless things are extremely serious.

How many warnings before dismissal in the UK?

The law doesn't set a magic number of warnings for capability dismissals. However, for ordinary poor performance, tribunals expect to see a stepped approach unless the situation is extreme.

Broadly:

• For performance: often at least one formal warning and a fair review period, sometimes more.
• For conduct: gross misconduct can justify dismissal without warnings; minor misconduct usually needs a similar stepped approach.

You should also check your contract and disciplinary/performance policies — if you've promised a particular structure, the tribunal will expect you to follow it.

Watch out for hidden legal risks (disability, discrimination, pregnancy)

Performance issues are rarely "pure". Always ask:

• Could there be an underlying disability or health condition affecting performance? See our guidance on when poor performance is actually a sickness or disability issue.
• Are there pregnancy, maternity or other family-related issues in play?
• Are there any protected characteristics that might make your approach look discriminatory?

Under the Employment Rights Act 2025, family-friendly rights and protections are strengthening from April 2026 onwards, with day-one paternity and parental leave and tighter protection around maternity and flexible working.

Disability discrimination and related claims are also increasing and can attract higher awards than unfair dismissal.

How the Employment Rights Act 2025 changes the risk calculus

Until now, many SMEs quietly relied on the two-year qualifying period for ordinary unfair dismissal as a comfort blanket. That goes from two years to six months from 1 January 2027 under the Employment Rights Act 2025.

Key changes:

• Employees will gain unfair dismissal protection much sooner — six months of service instead of two years.
• There will be no statutory cap on compensation for unfair dismissal, increasing the potential downside.
• Because of the "commencement approach", employees who start as early as July 2026 will gain unfair dismissal rights on 1 January 2027 if still employed.

In other words, the window where you can casually fire people without worrying about unfair dismissal is closing. You need decent performance processes for relatively new employees, not just the old timers.

Also worth being aware of: if a performance process gets messy, you may also need to think about what to do if they raise a grievance during the performance process. And for more complex situations involving senior staff, it's worth reading about what happens when an underperforming employee also holds shares.

When to involve solicitor-led HR rather than guessing

You should consider involving solicitor-backed HR support for performance management and dismissal when:

• Performance issues are serious and dismissal is realistically on the table.
• There may be disability, pregnancy, whistleblowing or other "automatically unfair" angles.
• You already have grievances or accusations of unfair treatment in the mix.
• You're dealing with senior staff, board members or founder-adjacent roles.

This isn't just about process — it's about strategy, reputational risk and legal privilege.

Poorly worded emails to a generic HR provider are unlikely to be privileged and can be ordered for disclosure if things go to tribunal.

Because Electra HR is powered by Bonsai Law, an SRA-regulated firm, you get performance management support with a clear route to legal professional privilege when we step over into legal advice.

If you're already thinking "can I dismiss this person for poor performance?", you're in the risk zone. Talk to us about performance management and dismissal — we can help you work out whether you actually have a performance problem or something else, run a fair documented process, and avoid performance management morphing into an unfair dismissal or discrimination claim.