The employee disciplinary process is where UK employers win or lose tribunal claims, long before a claim form exists. Run it properly and a fair outcome, up to and including dismissal, will usually hold. Run it badly and a strong case against the employee can collapse on procedure alone. Once the process is broken, the facts stop mattering. 

This guide walks through each step against the ACAS Code of Practice on Disciplinary and Grievance Procedures, the standard a tribunal will measure you against. It also covers what ignoring the Code costs: an increase of up to 25% on any award. It is written for SME owners and managers who handle discipline themselves, without an HR department behind them. 

One caution before the steps. This is educational guidance, not legal advice. Where a case involves discrimination allegations, whistleblowing, or anything you cannot see the bottom of, take advice before you act. This guide covers England, Scotland and Wales. Northern Ireland has its own code and its own dismissal rules, so take Northern Ireland advice separately. 

First, confirm discipline is the right process 

Three workplace processes get confused with each other, and the confusion produces unfair dismissals. 

Conduct is about choice. The employee can meet the standard and will not. Persistent lateness, unauthorised absence, insubordination, dishonesty, misuse of company property: these are conduct matters. Conduct is what the disciplinary procedure exists for. 

Capability is about ability. The employee is trying and cannot meet the standard, whether through skill, aptitude or health. That calls for a capability procedure, often built around a structured performance improvement plan, not a disciplinary one. Some employers run capability through their disciplinary procedure; a separate capability route is the better practice. Discipline someone for what they cannot help and you hand their solicitor the opening page of the claim. 

A grievance points the other way. It is a complaint the employee raises against the business or a colleague, and it runs through a separate formal grievance procedure with its own steps. 

The three cross over in real life. An employee facing a disciplinary hearing raises a grievance about the manager running it, mid-process. That is a legal right, not a delaying tactic, and you cannot brush it aside. Deal with the grievance first, or run both processes in parallel with different people handling each. Either can be fair. Ignoring one of them cannot. 

So ask the question at the start, in writing, before the first letter goes out. Will not is conduct. Cannot is capability. The answer decides the procedure, the evidence you need, and the legal test a tribunal will apply. 

The employee disciplinary process at a glance 

The ACAS Code gives a fair disciplinary procedure its shape. Five steps: 

1. Establish the facts through a prompt, fair investigation. 
2. Put the allegation in writing, with the evidence and the possible outcomes. 
3. Hold a disciplinary hearing, with the right to be accompanied. 
4. Decide the outcome and confirm it in writing, with reasons. 
5. Offer an appeal to someone not previously involved. 

The Code itself is short, and worth reading once in full. ACAS publishes a fuller step-by-step guide to the disciplinary procedure, and GOV.UK summarises the employer's duties. Tribunals must take the Code into account when judging fairness. The sections below cover what each stage demands, and where employers slip. 

Step one: establish the facts before you accuse 

Every defensible disciplinary process starts with an investigation. Its job is to find out whether there is a case to answer. It is not there to build a prosecution. 

What the investigation looks like depends on the allegation. A timesheet dispute might need one morning with the records. A bullying allegation might need interviews with four witnesses. The test is reasonableness: did you gather what a fair-minded employer would have gathered, including the evidence that helps the employee? 

That last part is the piece employers miss. An investigation that only collects material against the employee is not an investigation. Tribunals notice when the helpful evidence never made it into the pack. 

Keep the investigator and the decision-maker separate wherever you can. The person who gathers the evidence should not chair the hearing or decide the outcome. In a five-person business this is genuinely hard. The owner may have witnessed the incident, investigated it, and be the only person senior enough to decide. Where the roles cannot be separated, record that fact and the reason, and consider an external investigator for anything that could end in dismissal. The smaller the business, the more work the paperwork has to do. 

Suspension needs care. It is a tool for serious cases where the employee's presence could contaminate evidence, pressure witnesses, or create a risk to people or the business. It is not a verdict, and it should never be automatic. If you do suspend: normally on full pay, for the shortest period possible, reviewed regularly, and explained in writing as a neutral step. A long, unexplained suspension reads to a tribunal like a decision already made. 

Investigation notes are evidence. Record who you spoke to, on what date, what they said, and which documents you reviewed. Write them at the time. Notes reconstructed after a solicitor's letter arrives are worse than no notes at all. 

Step two: put the allegation in writing 

If the investigation shows a case to answer, the employee gets a letter before any hearing takes place. Under the ACAS Code, that letter must carry enough detail for the employee to prepare a genuine answer. In practice it needs five things: 

1. The specific allegation, with dates and examples. "Your conduct in the customer meeting on 14 March" beats "your recent attitude". 
2. Copies of the evidence: witness statements, documents, records. 
3. The possible outcome if the allegation is upheld, stated honestly. If dismissal is a possible outcome, the letter must say so. 
4. The time, date and place of the disciplinary hearing. 
5. The right to be accompanied. 

Two practitioner points on this letter. 

Send the evidence with the invitation, not at the hearing. An employee who first sees the case in the room has had no chance to prepare, and a tribunal will read the hearing as an ambush. Everything the decision will rely on goes in the pack. Anything held back cannot fairly be relied on later. 

Give real notice. The Code requires enough time to prepare, and no statute fixes the number. A hearing the following morning is not reasonable notice for anything serious. Two or three working days is a sensible floor for a straightforward matter; allow longer where the pack is thick or the stakes are high. 

And watch the wording. The invitation describes an allegation, not a finding. Letters that say "your misconduct" rather than "the alleged conduct" turn up in tribunal bundles as proof the outcome was decided before the hearing started. 

Step three: hold the disciplinary hearing 

The disciplinary hearing is the employee's opportunity to answer the case. It is not a formality on the way to a decision you have already reached, and it has to look and feel that way on the record. 

The right to be accompanied is statutory. Under section 10 of the Employment Relations Act 1999, a worker who reasonably requests it may bring one companion, a colleague or a trade union representative, to any hearing that could result in a formal warning or other disciplinary action. The companion may put the worker's case, sum it up, respond on the worker's behalf to views expressed in the hearing, and confer with the worker. What the companion cannot demand is to answer questions put directly to the worker. If the chosen companion cannot attend, the worker can propose a new time, and if it is reasonable and falls within five working days of the original date, you must move the hearing to it. Refusing any of this is a free-standing breach of the law, however well you handle everything else. 

Run the hearing in three movements. Set out the allegation and walk through the evidence. Give the employee the floor to respond in full, with their companion. Then adjourn. Almost no outcome should be announced in the room. The adjournment is where the decision gets made and documented, and it protects you against the argument that the outcome was pre-cooked. 

Put two people on your side of the table: one to chair, one to take notes. The chair cannot ask fair questions and keep a fair record at the same time. The notes do not need to be word-for-word, but they must capture what was asked, what was answered, and anything new the employee raised. Share them with the employee afterwards and invite corrections. Twelve months later, an agreed note is worth ten disputed ones. 

If the employee raises something new, a witness you never interviewed, a document you never saw, adjourn and investigate it. Pressing on regardless converts new evidence into a procedural defect. 

If the employee does not attend, rearrange at least once, and warn in writing that a further failure to attend without good reason may mean the hearing goes ahead in their absence, decided on the evidence available. Deciding in absence is a last resort, not a shortcut. 

Step four: decide the outcome and confirm it in writing 

A fair conduct decision has two parts: a genuine belief in the misconduct, held on reasonable grounds after a reasonable investigation, and a sanction a reasonable employer could have imposed. A tribunal does not ask whether it would have dismissed. It asks whether your decision sat within the band of reasonable responses. 

For ordinary misconduct, the ladder usually runs: first written warning, then final written warning, then dismissal or another serious sanction, such as demotion where the contract allows it. A first offence of ordinary misconduct rarely justifies dismissal. Gross misconduct, such as theft, violence or serious dishonesty, can justify dismissal without notice for a first offence, but only after the full process has run. Gross misconduct changes the available sanction. It does not remove a single step. 

Consistency counts. If the last person who did the same thing received a warning, dismissing this employee needs a documented reason for the difference. Tribunals read unexplained inconsistency as unfairness. Length of service, a clean record, and any mitigation the employee raised belong in your thinking too, and the outcome letter should show they were considered, whether or not they changed the result. 

The outcome letter carries the decision, the reasons for it, the evidence relied on, how long any warning stays live, what improvement is expected, what happens if the conduct repeats, and the right of appeal with a deadline and a named person to write to. "We have decided to issue a final written warning" with nothing behind it is not an outcome letter. The thinking must be on the page. At tribunal, the letter is the decision; reasoning that never made it into writing may as well not exist. 

Step five: offer the appeal and run it properly 

The appeal is a required step under the ACAS Code, not a courtesy. The employee should have a clear window to appeal, and the appeal should be heard by someone not previously involved, more senior than the original decision-maker where the size of the business allows. 

In a small company that can mean a director who deliberately stayed out of the case, or an external HR professional brought in for this one task. What it cannot mean is the original decision-maker marking their own homework. 

A genuine appeal re-examines the decision. It can rehear the whole case or review the specific grounds the employee raises, and it can cure some earlier procedural defects if it is thorough. A rubber stamp cures nothing, and tribunals can spot one from the timeline alone: an appeal heard, decided and rejected within a day of the letter arriving looks exactly like what it is. Confirm the appeal outcome in writing, with reasons, and say clearly that it is the final stage of the internal process. 

How long should the employee disciplinary process take? 

No statute fixes a deadline for the employee disciplinary process, and that absence traps employers in both directions. 

Move too fast and the process looks pre-judged. An investigation, hearing and dismissal completed inside forty-eight hours reads as a formality, whatever the evidence. The employee needs genuine time to prepare at every stage, and your file needs to show they got it. 

Move too slowly and the delay itself becomes the unfairness. An allegation left hanging for two months, an employee suspended with no update, a hearing adjourned indefinitely: each one damages the employee, and tribunals treat avoidable delay as a breach of the Code's requirement to act promptly. 

The working rule: each step follows the last without avoidable delay, and every gap has a recorded reason. A pause to interview a witness who was on leave is defensible. A pause because the owner was busy is not, and saying so in the file does not make it so. 

The paper trail that holds the process together 

If a claim lands, the tribunal reconstructs your disciplinary procedure from documents, not memories. Eighteen months after the event, the file is the process. It should hold: 

1. The investigation notes, dated, with the evidence gathered. 
2. The invitation letter and the evidence pack sent with it. 
3. The hearing notes, shared with the employee, with any corrections. 
4. The outcome letter, with reasons. 
5. The appeal correspondence and the appeal outcome. 

Missing documents are read against you. If the hearing notes do not exist, the tribunal's working assumption is that the hearing was not fair, and your recollection will not displace it. In practice, an absent record is treated as an absent step. 

None of this needs to be sophisticated. A single folder per case, filled as you go, beats any system built after the claim arrives. 

The 25% uplift, and what a broken process costs 

Under section 207A of the Trade Union and Labour Relations (Consolidation) Act 1992, where an employer unreasonably fails to follow the ACAS Code, a tribunal may increase the award by up to 25% in the claims the section covers, which include unfair dismissal and discrimination. On a five-figure unfair dismissal award, the uplift alone can outprice the cost of having run the process properly many times over. How those awards are built up is a subject of its own; our guide to unfair dismissal compensation breaks it down. 

The section cuts both ways. An employee who unreasonably fails to follow the Code, for example by refusing to appeal, can see their award reduced by up to 25%. That is worth knowing, but it is a shield you never want to need. 

The uplift is only the visible cost. Defending a claim consumes management time for months, whatever the outcome, and the Employment Rights Act 2025 has moved the ground under dismissal law: more scrutiny of process, not less, is the direction of travel. From 1 January 2027 the unfair dismissal qualifying period drops to six months and the cap on the compensatory award is removed. A disciplinary procedure that was marginal in 2023 is exposed now. 

Five slips that undo careful employers 

Most tribunal losses on process are not caused by malice. They are caused by shortcuts under pressure. These five appear again and again. 

1. Deciding first, processing second. A pre-drafted outcome letter in the file, or an invitation that reads like a verdict, sinks the case regardless of the misconduct. 
2. One person wearing every hat. Investigator, chair and appeal judge should be three people. Where they cannot be, the file must show you knew it and managed it. 
3. Evidence handed over late. Anything the employee sees for the first time in the hearing room was withheld, in the tribunal's eyes. 
4. Delay. Weeks of silence between investigation and hearing, or hearing and outcome, read as either indifference or manoeuvring. Neither helps you. 
5. Treating gross misconduct as a shortcut. Instant dismissal without a hearing is one of the most common, and most avoidable, ways employers turn a winnable case into a payout. 

Each of these is cheap to prevent and expensive to repair. The prevention is a written disciplinary procedure, followed every time, with the paperwork done as you go rather than reconstructed afterwards. 

Find out whether your process would hold, before it gets tested 

Most SME owners discover the holes in their disciplinary process at the worst moment: after a dismissal, when the claim arrives. Finding out earlier costs nothing. The free HR Health Check takes under a minute and lets you know whether your HR fundamentals sit at Red, Amber or Green, across the areas a tribunal would examine first. Take the HR Health Check and see where you stand while the process is still yours to fix.