Deadlock letter explained: what it means and when it matters

A deadlock letter is a message from your energy supplier saying it cannot resolve your complaint, or that it has reached its final position.

It matters because it can let you take your complaint to the Energy Ombudsman before waiting the full 8 weeks.

What does a deadlock letter mean?

A deadlock letter usually means the supplier says it has reached its final position on the complaint.

It should explain the supplier’s position and tell you that you can contact the Energy Ombudsman if you remain unhappy.

It does not automatically mean the supplier is right or wrong. It simply means the complaint has reached a point where an independent review may be possible.

Is it the same as a final response?

In practice, people often use phrases like:

• deadlock letter
• final response
• final decision
• complaint outcome

The wording can vary, but the important point is whether the supplier is telling you it has finished dealing with the complaint and you can go to the Ombudsman.

If you are unsure, check the letter or email for wording about the Energy Ombudsman.

Do I need a deadlock letter?

Not always.

You can usually go to the Energy Ombudsman if:

• you have received a deadlock letter, or
• 8 weeks have passed since you complained and the issue is still unresolved

So if 8 weeks have already passed, you may not need to wait for a deadlock letter.

What should I do when I receive one?

Keep it safe.

Save:

• the deadlock letter or email
• the date it was sent
• your complaint reference number
• any explanation the supplier gave
• any offer or outcome they proposed

Then decide whether you are satisfied with the response.

If you are not satisfied, organise your evidence before escalating.

What if the supplier has not sent one?

If the supplier has not sent a deadlock letter and 8 weeks have not passed, you may need to keep the complaint with the supplier for now.

You can still make the complaint stronger by asking for:

• a written explanation
• a clear next step
• a timescale
• confirmation of what readings, bills, meter checks, or account details they have relied on

Key point

A deadlock letter is not a guarantee that the Ombudsman will agree with you.

It is a gateway into the Ombudsman process.

Your case will usually be clearer if you can show the timeline, evidence, supplier response, and the outcome you are asking for.