UK broadband speeds, evidence and provider complaints
Understand contract speed information, document a persistent fault and use the provider complaint and ADR process under current UK rules.
Start with the free diagnostic steps. Affiliate links appear only where a product category could address the problem identified in this guide.
Key takeaways
- Find the minimum, normally available, maximum and advertised speed information supplied for the fixed service.
- Use controlled Ethernet tests and the provider’s own diagnostic to build fair evidence.
- From 8 April 2026, unresolved eligible complaints can generally reach ADR after six weeks or earlier with deadlock.
Start with the information for your contract
For fixed broadband, Ofcom says the provider should clearly explain minimum, normally available, maximum and advertised download and upload speeds when the service is sold. Find the order confirmation, contract summary and any minimum guaranteed speed statement. The exact terminology and remedy can depend on the service, date and provider code, so use your own documents rather than a generic online number.
Separate line or router input speed from Wi-Fi performance. A contractual estimate may apply to the connection delivered to provider equipment under specified conditions, while a browser test on a wireless device includes the home radio link. Ask the provider which measurement it accepts and at what boundary.
Build evidence that can be reproduced
Use a capable device connected by Ethernet directly to the router where practical. Pause other transfers, disable an optional personal VPN for the comparison, and run several tests at different times. Record date, time, device, browser, connection type and whether the provider’s official status page reported an issue. Keep the full range rather than selecting only the worst result.
Run the provider’s own line or account diagnostic too. It may be able to see synchronisation, optical or provisioning information that a public browser cannot. Photograph unusual router lights and note disconnections. Do not repeatedly factory-reset equipment unless instructed, because a reset can erase evidence and working settings.
Report the fault before making a formal complaint
Contact support with a concise description: when the problem began, whether it affects all devices, Ethernet and Wi-Fi comparisons, router-light state and the steps already tried. Ask for a fault or case reference. Follow reasonable diagnostic instructions and record appointments, promised actions and messages.
A slow result does not automatically establish breach of contract. The provider must have a fair opportunity to investigate the line and equipment. Equally, repeated wired evidence should not be dismissed as merely “Wi-Fi” without the conditions being considered.
Use the provider’s formal complaints process
If normal support does not resolve the issue, state clearly that you are making a formal complaint and describe the resolution sought. That may be repair, accurate information, compensation where applicable, a price remedy or release from the contract where the relevant rules and terms allow it. Keep a copy and request a complaint reference.
Ofcom collects complaints and regulates the sector but does not normally decide an individual billing or service dispute. The provider’s complaints code should identify its approved Alternative Dispute Resolution scheme. ADR is independent and free for eligible consumers.
The current six-week ADR rule
From 8 April 2026, Ofcom’s strengthened rule reduces the unresolved-complaint wait for ADR from eight weeks to six weeks. A consumer can generally take an eligible complaint to the provider’s ADR scheme when six weeks have passed since it was first raised, or earlier when the parties reach deadlock and the provider issues a deadlock letter.
Check the current Ofcom page before acting because eligibility and process details matter. Submit an organised timeline, contract information, test conditions, provider responses and the remedy requested. Do not overstate what a browser test proves; explain that it measures the device-to-test-server path and include the provider’s own results where available.
Compensation and safety
Some providers participate in Ofcom’s automatic compensation scheme for qualifying delayed repairs, missed appointments or delayed service starts. Eligibility, amounts and exclusions can change, so use Ofcom and the provider’s current information rather than a copied figure. Keep appointment and outage records.
Do not open provider street cabinets, optical equipment or powered network hardware. Report damaged external infrastructure, exposed cables or electrical danger through the provider’s emergency route. This guide is general information, not legal advice; for a complex loss or contract dispute, obtain appropriate independent advice.
Recommended next checks
Compare results beside the router, in the problem location and over Ethernet where possible. Repeat under the same conditions rather than relying on one run. LumaProbe’s browser measurements describe the complete path to its server, so use them to narrow the fault—not as a substitute for a provider line diagnostic.
Sources and further reading
- Ofcom: checklist for a new broadband contract
- Ofcom: making a complaint and using ADR
- Ofcom: six-week ADR rule from 8 April 2026
External guidance can change. Sources and links were checked on 19 July 2026.
More help
Browse all internet and Wi-Fi guides, read how LumaProbe tests connections, or report a correction through LumaContact.