A guide to deadlock letters

Before you can bring a complaint to an ombudsman, you’ll have to allow a period of time for your provider to look into the complaint – 6 weeks for communications complaints. 
Sometimes, however, they may issue a final response letter, which allows you to access our service before 6 weeks have passed. This letter is commonly known as a deadlock letter. This guide explains what a deadlock letter is, when you might receive one, and what you can do next. 
 

What is a deadlock letter?

If you’ve raised a complaint with your communications provider and it hasn’t been resolved, your provider may issue a deadlock letter.

A communications provider is required to issue a deadlock letter where it does not intend to take any additional steps to resolve a complaint.

Receiving a deadlock letter means you can bring your unresolved dispute to Communications Ombudsman without having to wait for the usual complaints period to pass (currently 6 weeks).

What should a deadlock letter include?

A deadlock letter, sometimes called an ADR letter, is the letter your provider must send you when all three of the following apply:
• It has told you the outcome of its investigation into your complaint.
• You have told it that you’re not happy with that outcome.
• It does not plan to take any further steps that would lead to a different outcome.

Once all three apply, your provider must send the letter straight away.
Ofcom’s rules set out what the letter must contain. It must:
• Be written in plain English.
• Be about your complaint only, without unrelated information such as marketing.
• Tell you that, because your complaint can’t be resolved to your satisfaction, you can take it to an alternative dispute resolution (ADR) scheme free of charge.
• Give the name and contact details of the ADR scheme your provider is a member of, and confirm that the scheme is independent of your provider.
• Be sent in a form you can keep, such as a letter or email.
 

Do I need a deadlock letter to contact Communications Ombudsman?

Not always - for complaints first raised with your provider on or after 8 April 2026, you can bring an unresolved dispute to Communications Ombudsman once your provider has had six weeks to try to resolve it.

If you raised your complaint before 8 April 2026, the previous eight-week waiting period applies.

However, if your provider issues a deadlock letter before that waiting period has passed, you don’t need to wait. You can bring your dispute to us straight away, provided your complaint is eligible for our service. 
 

How do I get a deadlock letter?

You’ll first need to raise your complaint directly with your communications provider and give them an opportunity to resolve the issue.

Keep a record of the contact you have with your provider, including relevant emails or letters, details of phone calls and any evidence relating to your complaint.

If your provider offers a resolution you’re not happy with, let them know. If they’re unwilling to do more to resolve your complaint, they should issue a deadlock letter.

If you receive one, keep a copy as you may need it when bringing your dispute to Communications Ombudsman.

What should I do if I receive a deadlock letter?

Keep a copy of the letter or email and any supporting evidence relating to your complaint.

When you bring your dispute to us, it’s helpful to provide evidence of the contact you’ve already had with your provider. This might include emails or letters, bills, screenshots or details of phone calls, including dates, times and the names of people you spoke to.

When creating your case online, you’ll be asked whether the relevant waiting period has passed or whether you’ve received a deadlock letter allowing you to bring your dispute to us sooner. You can then provide details of what has happened and upload supporting documents relating to your complaint.

How long do I have after receiving a deadlock letter?

You must bring your dispute to Communications Ombudsman within 12 months of receiving your deadlock letter.  

What happens when I bring my dispute to Communications Ombudsman?

Communications Ombudsman provides free, independent and impartial dispute resolution for unresolved complaints between consumers and communications providers.

We’ll consider the information and evidence provided by both you and your provider to understand what has happened and reach a fair and independent outcome.

Depending on the circumstances and the evidence available, outcomes can include practical action to put an issue right, an apology or a financial award where appropriate.

If you’ve received a deadlock letter, or your complaint has remained unresolved after the relevant waiting period, find out more about our process and check whether we can help with your dispute.