Arbitration is when a third party makes a decision on a dispute to resolve it.

Arbitration is delivered by a neutral person (an 'arbitrator'). The arbitrator is impartial. This means they do not take sides. The arbitrator considers the arguments from both sides of the dispute at a meeting ('hearing'). They then make a decision based on the evidence presented.

Acas provides:

  • collective arbitration – for disputes between an employer and a group of employees
  • individual arbitration – for disputes about flexible working or unfair dismissal, between an employer and an employee

Before trying arbitration

It's better if both sides, or their representatives, can resolve the dispute between themselves first. Both sides should try and work something out together or use Acas conciliation to help reach an agreement.

Find out more about using Acas conciliation services:

If conciliation does not work, arbitration can help resolve the dispute.

How Acas arbitration works

Before arbitration starts, both sides must agree to accept the arbitrator's decision.

Acas appoints an arbitrator and arranges a date for a hearing. The hearing is held remotely on Microsoft Teams or Zoom.

Before the hearing, both sides should send the arbitrator and each other written statements of their case and other supporting documents. The arbitrator will only consider evidence presented before the hearing.

At the hearing, the arbitrator will:

  • confirm the matter they're being asked to make a decision on
  • ask both sides to explain their case – each side is allowed to talk without interruption
  • ask questions to make sure both sides understand all the issues
  • discuss the case with both sides
  • allow both sides to ask questions of each other, based on the evidence presented at the hearing
  • ask both sides to sum up the main points for them to consider

Hearings normally last for about half a day.

After the hearing the arbitrator will make a decision in writing, called an 'award'.

Acas will send the award to both sides at the same time within:

  • 21 days for collective disputes
  • 14 days for individual disputes

Using collective arbitration

Collective arbitration can help resolve a dispute between an employer and a group of employees if:

  • collective conciliation does not work
  • your trade union recognition agreement includes collective arbitration as an option for resolving disputes

Before collective arbitration starts, both sides must agree to accept the arbitrator's decision. They do this by setting out the issues in the dispute, called 'terms of reference', which both sides agree to and confirm by signing an Acas form.

For collective disputes, the arbitrator's decision is not legally binding but binding in honour. This means that once the arbitrator makes a decision, neither side can go to court to get it changed at a later date.

Using collective mediation

Your trade union recognition agreement might include collective mediation as well as, or instead of collective arbitration.

The collective mediation process is similar to arbitration. The mediator will work with both sides on the day to see if a resolution is possible. If the 2 sides cannot reach agreement on the day, the mediator makes recommendations for both sides to consider.

How to request collective arbitration or mediation

To request collective arbitration or mediation:

Using individual arbitration

If you cannot resolve a dispute through early conciliation, you might be able to use individual arbitration instead of going to an employment tribunal.

Who can use individual arbitration

You can use this service if:

  • your dispute is only about flexible working or unfair dismissal
  • both sides agree to use arbitration

You cannot use arbitration for any other type of individual dispute. For example, you cannot use individual arbitration if your dispute is about both flexible working and discrimination, or both unfair dismissal and unpaid wages.

If your dispute is suitable for arbitration

Acas will tell the employment tribunal that the dispute will be resolved through arbitration instead of through the tribunal.

The arbitrator's decision is legally binding and will give a similar outcome to going to an employment tribunal.

To find out more about Acas's individual arbitration service:

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