BT has admitted that underground telecoms cables in east London were damaged by workmen over the weekend, causing thousands of phone lines to be disconnected.

Workmen were carrying out maintenance in a tunnel on Saturday night, and plunged local residents into a communications black spot. The workers were third-party contractors not directly employed by BT, and the firm has declined to name the contractor involved.

Emergency repair work is underway, but many local residents are still without service, according to a BT spokesman.

Although reports yesterday suggested that there were only 500 remaining affected broadband users, a spokesman revealed this morning that approximately 40 per cent of telephone lines have yet to be reconnected. He added that engineers are working round the clock to resolve the situation.

New figures from BT have since been released stating that, out of 75,000 connections affected, some 50,000 are now working.

BT hopes that all services will be reconnected or re-routed before the end of the day, but the spokesman explained that it is making "no promises". In a statement the firm added: "Given the complexity of the damage suffered, it is not yet possible to accurately predict when all services will be restored."

The location of the fault has not been revealed for security reasons.