Poor Performance at Work: A Fair, Lawful Process in the UK

Poor performance at work can drain productivity, frustrate teams and put real pressure on a small business’ margins.

The good news? With a clear process and the right documents in place, you can deal with underperformance fairly, lawfully and with minimal disruption - and either turn things around or make a safe, defensible decision to end the employment.

Below, we break down what “poor performance” actually means under UK law, how to run a fair capability process step-by-step, key risks to watch for, and the essential policies and contracts that protect your business from day one.

What Counts As Poor Performance At Work?

In UK employment law, poor performance (often called “capability”) is about an employee’s ability to do the job to the required standard. It’s different from misconduct (behaviour), and the way you handle it should reflect that distinction.

• Capability issues: consistently missing targets, slow output, errors/quality concerns, inability to use required systems after training.
• Conduct issues: lateness, rudeness, insubordination, breaches of policy, dishonesty.

Getting this right matters because capability and conduct require different procedures. If you treat a capability case like a disciplinary matter, you can accidentally skip steps that a tribunal would expect in a fair performance process. For a deeper look at the difference and why it matters, see our guidance on conduct vs capability.

As a starting point, make sure the role’s standards are clear, measurable and linked to business needs. If you’ve never defined acceptable performance for the role, it’s difficult to prove that outcomes fall below a reasonable benchmark.

Set Clear Standards And Gather Evidence

Before you jump into formal steps, sense-check your foundations. Tribunals look closely at what standards you set and how you’ve assessed the employee against them.

Be Specific About Expectations

• Define KPIs, deadlines and quality metrics in writing.
• Provide job descriptions that reflect the real role.
• Make sure targets are achievable and consistent with colleagues in similar roles.

Role clarity is easiest to maintain when it’s baked into your Employment Contract and reinforced in your Staff Handbook and policies. That way you can show the employee knew what was required.

Collect Balanced Evidence

• Performance data: sales numbers, error rates, customer feedback, output per hour/day.
• Examples: specific instances of missed deadlines or quality failures.
• Support provided: training records, mentoring notes, workload adjustments.
• Comparators: how peers with similar duties are performing (be mindful of confidentiality).

Keep your records factual and consistent. If performance dips after a change (e.g. new software), factor that into your assessment.

Check For Underlying Causes

Poor performance can be linked to health, disability, workload, changes in duties, lack of training or personal issues. If health or disability is a factor, the Equality Act 2010 requires you to consider reasonable adjustments. If illness is long-term, capability management may intersect with sickness absence - our overview of capability dismissal for ill health covers that process.

Follow A Fair Capability Process Step-By-Step

UK tribunals expect employers to follow a reasonable, staged process for performance cases. While the ACAS Code of Practice on Disciplinary and Grievance Procedures applies more directly to conduct, the same fairness principles apply: clear standards, warnings, time to improve, and a genuine review.

1) Informal Feedback And Support

Start with a conversation. Explain the performance concerns, the impact on the business, and what “good” looks like. Ask for the employee’s perspective, identify any training needs, and agree immediate supports (shadowing, refresher training, mentoring).

Confirm the discussion by email so there’s a contemporaneous record.

2) Move To A Formal Performance Meeting

If performance doesn’t improve, invite the employee to a formal capability meeting in writing. Set out:

• The specific performance concerns and evidence.
• The standards expected and the gap observed.
• That the meeting could result in a formal warning.
• The right to be accompanied (by a colleague or trade union representative).

At the meeting, discuss the concerns, consider any mitigation, and decide on next steps. Often, that next step is a structured Performance Improvement Plan (PIP).

3) Set A PIP With Realistic Goals And Timeframes

A well-drafted PIP gives the employee a fair chance to improve. It should include:

• Clear targets and metrics (e.g. reduce error rate to under 2% within 6 weeks).
• Specific support: training, check-ins, access to tools, reasonable adjustments.
• Timescales: a reasonable review period (often 4–12 weeks, depending on the role).
• Consequences: what may happen if improvement isn’t sustained (e.g. a final written warning).

Meet regularly during the PIP and keep notes. If the employee hits the targets, great - confirm this in writing and return to normal management. If they don’t, you may escalate.

4) Escalate Warnings Where Needed

Where there’s insufficient improvement, you can issue a formal written warning, and then a final written warning if performance still doesn’t meet the standard. Each stage should come with:

• A meeting with the right to be accompanied.
• Written outcome letters explaining evidence, expectations and next steps.
• A right of appeal to someone not previously involved, where practicable.

Your Staff Handbook should set out the overall process, timescales and appeal pathways. If you don’t have one, consider implementing a Staff Handbook and performance policy now so expectations are consistent across your team.

5) Consider Alternatives To Dismissal

Before terminating, think about whether lesser measures could work:

• Extended PIP period with additional support.
• Change of duties or transfer to a suitable vacancy.
• Additional training or supervision.

Document why alternatives would or wouldn’t be reasonable in the circumstances. This can be crucial if your decision is later scrutinised.

6) Dismissal For Capability (If There’s No Sustainable Improvement)

If, after warnings and a fair opportunity to improve, performance remains below standard, a dismissal for capability can be fair. Invite the employee to a final meeting, confirm the risk of dismissal, consider any new representations, then issue the decision in writing with reasons, notice (or payment in lieu) and the right of appeal.

If you’re unsure about thresholds and timing, our guide to whether you can dismiss for poor performance walks through when warnings are required and the risks of skipping steps.

Legal Risks To Watch (And How To Avoid Them)

Most disputes about poor performance at work aren’t about the underlying performance - they’re about process, fairness and protected rights. Keep these risks front-of-mind.

Unfair Dismissal (Employment Rights Act 1996)

To dismiss fairly, you need a potentially fair reason (capability is one of them) and a fair process. The core questions tribunals ask:

• Were standards clear and reasonable?
• Did you give warnings and enough time and support to improve?
• Was dismissal within the range of reasonable responses?

Employees usually need two years’ continuous service to claim ordinary unfair dismissal, but don’t rely on the two-year threshold alone - automatically unfair reasons (e.g. health and safety, whistleblowing) have no service requirement.

Discrimination And Reasonable Adjustments (Equality Act 2010)

If poor performance is linked to disability, pregnancy or other protected characteristics, you must take extra care. Apply standards consistently, consider medical evidence, and explore reasonable adjustments to mitigate the disadvantage (training time, adjusted targets, assistive tech). Failure to do so risks discrimination claims, even for short-service employees.

Wrongful Dismissal And Contract Risk

Terminate in line with contractual notice, PILON clauses and any contractual capability process. If you cut corners, the employee may claim wrongful dismissal. Keeping your Employment Contract up to date helps you avoid accidental obligations that tie your hands later.

Procedural Fairness (ACAS Code)

While capability isn’t always treated as “disciplinary,” fairness principles still apply: clear information, right to be accompanied, time to prepare, and a right of appeal. Significant unjustified deviations from the ACAS Code can uplift awards in tribunal cases.

Data Protection (UK GDPR And Data Protection Act 2018)

Performance management involves personal data. Keep records accurate, necessary and secure. Limit access to those with a management need to know, and be mindful of data retention - don’t keep performance notes longer than you need them.

Overlapping Issues: Sickness, Grievances And Whistleblowing

PIPs can overlap with sickness absence, grievances or whistleblowing. Pause or adjust processes appropriately and avoid any suggestion that performance steps are retaliation. If an employee raises a grievance during capability, consider dealing with it before proceeding to the next stage or running both in parallel with care.

Essential Policies And Documents That Make Capability Management Easier

The right documents do a lot of heavy lifting when managing poor performance at work. They set expectations, embed your process and reduce the risk of disputes.

Employment Contracts

• Define the role, place of work, hours, reporting lines and flexibility clauses.
• Include notice, PILON and the ability to make reasonable changes to duties.
• Reference performance standards and policies that apply to the role.

If your templates are out of date or you’ve grown since you first hired, it’s worth reviewing your Employment Contract now to ensure it supports capability management and lawful termination.

Policies And Staff Handbook

• Performance and capability policy that mirrors the staged process set out above.
• Disciplinary and grievance policies aligned with the ACAS Code.
• Equality, disability and reasonable adjustments policy.
• Training and probation policies for new starters.

Bringing these together in a single Staff Handbook makes it easy to keep things consistent and shows you take fairness seriously.

Performance Improvement Plans

Use a standard PIP template for consistency, but tailor it to each role and situation. The PIP should set measurable goals, timescales and supports, and clearly explain potential outcomes if improvement isn’t sustained. Our article on running a Performance Improvement Plan covers best practice and common pitfalls.

Probation Periods

Probation allows you to assess capability early. Make sure your contract clearly states the probation length, extension right and review points. You should still follow a fair process - but the thresholds and timings are more flexible in probation. If you’re fine-tuning your approach with new starters, see our guide to the probation period.

Decision And Outcome Letters

Outcome letters for warnings and dismissal should explain the evidence, your decision and the appeal process. Clear, careful drafting now can save you a lot of back-and-forth later and will be scrutinised if a claim arises.

Ending The Employment Fairly

When you do have to part ways, follow the steps to end an employment contract fairly - give notice or PILON, pay for untaken holiday, collect company property, close IT access and confirm restrictive covenants. A tidy exit reduces risk and protects your team.

When Can You Dismiss For Poor Performance (And What If The Employee Has Short Service)?

Dismissal for poor performance is usually fair only after warnings and a reasonable chance to improve. However, there are scenarios where earlier action may be reasonable:

• Probation: shorter timescales and simpler processes can be justified, subject to fairness and discrimination risks.
• Serious capability gaps: where the gap is so wide that no reasonable steps would bridge it in a reasonable period, particularly in safety-critical roles.
• Short service: employees with under two years’ service can’t generally claim ordinary unfair dismissal - but watch for automatically unfair and discrimination risks (which don’t require two years).

Even in these cases, a brief, fair process (meeting, opportunity to respond, written outcome, notice and appeal) remains best practice. It protects you against wrongful dismissal and discrimination claims and demonstrates reasonableness if challenged.

If you’re weighing up timing, our guide on whether you can dismiss for poor performance sets out the practical considerations so you can decide confidently.

Key Takeaways

• Poor performance at work is a capability issue - keep it distinct from conduct and follow a fair, staged process grounded in evidence and clear standards.
• Set expectations early in your Employment Contract and reinforce them with a clear Staff Handbook and performance policy.
• Start informally, then use a structured Performance Improvement Plan with measurable goals, regular check-ins and realistic timescales.
• Escalate warnings lawfully and document support given. Only move to dismissal when there’s no sustainable improvement and alternatives aren’t reasonable.
• Watch the big legal risks: unfair dismissal, discrimination and reasonable adjustments, wrongful dismissal, data protection and ACAS Code principles.
• Pay special attention to probation and short-service cases - you still need a fair process, even if it’s shorter. When termination is necessary, follow the steps to end an employment contract properly.
• If the situation blurs into behaviour or health issues, revisit the distinction between conduct vs capability, and consider whether sickness or disability adjustments are required.

If you’d like help drafting performance policies, running a capability process or reviewing your contracts, you can reach us at 08081347754 or team@sprintlaw.co.uk for a free, no-obligations chat.