What Is a Deadlock Letter

A deadlock letter is a written statement from a company confirming that its internal complaints process is exhausted and it cannot offer any additional resolution. In practical terms, it means the company is saying: "This is our final position — we cannot go any further."

The letter effectively unlocks your right to take the complaint to an independent ombudsman. Most ombudsmen require either 8 weeks to have passed or a deadlock letter before they will accept a referral. A deadlock letter bypasses the 8-week wait entirely.

The terminology varies between sectors and companies. In the energy and telecoms sectors, "deadlock letter" is commonly used. In financial services, you are more likely to see the phrase "final response letter". Both serve the same purpose.

Not every letter from a company amounts to a deadlock or final response. Look for specific language indicating the company's complaints process has concluded. Key phrases to look for include:

• "This is our final response to your complaint."
• "We are unable to take this matter any further."
• "We have now completed our investigation."
• "If you remain dissatisfied, you may refer this matter to [ombudsman name]."

Regulated companies — particularly energy suppliers and financial firms — are legally required to tell you which ombudsman or ADR scheme you can use, and many must include the contact details in any final response letter. If this information is missing, ask the company directly which scheme applies to your complaint.

When you receive a deadlock or final response letter, take the following steps immediately:

• Read it carefully. Check whether the company has offered any partial resolution — even a partial offer may be worth accepting if it covers your loss.
• Note the date. Most ombudsmen require you to refer the complaint within 6 months of the final response. Some schemes have different windows — check the specific rules for your sector.
• Gather your evidence. Compile all correspondence, the original complaint, the company's responses, and the deadlock letter itself.
• Refer to the appropriate ombudsman. Identify the correct ombudsman for your sector and submit your referral online or in writing.

You do not need legal representation to use an ombudsman. The process is designed to be straightforward and free for complainants.

If a company is taking a long time to respond but has not issued a deadlock letter, you still have options. After 8 weeks from the date of your original complaint, most ombudsmen will accept your referral regardless of whether the company has issued a final response.

You can also formally request a deadlock letter from the company if you feel the complaint is stuck. Some companies may be reluctant to issue one, but in regulated sectors such as energy and financial services, they are required to respond within prescribed timeframes and must inform you of your right to use an ADR scheme.

If a company refuses to engage at all, report this to the relevant regulator (such as Ofgem for energy or the FCA for financial services). Regulators can apply pressure and in serious cases take enforcement action.