The Metropolitan Police said detectives raided a one-bedroom flat in Shepherd's Lane, Harehills, Leeds.

Local residents said officers arrived and showed householders in the street photos of the bombers - Mohammed Siddique Khan, Shehzad Tanweer, Hasib Hussain and Jermaine Lindsay.

The men died when they exploded four bombs on three Tube trains and a bus in July 2005 killing 52 people.

Investigators do not believe any of the bombers, whose backgrounds have been thoroughly researched, ever lived at the flat. But they are looking for evidence to suggest the property was used as a base, or even to prepare the bombs.

The Harehills area of Leeds has never been central to the story of the bombings. It is a number of miles from the Beeston area, where three of the four bombers had connections, and the Hyde Park area, where their bomb factory was discovered.

Police stressed that the current resident of the flat, who is believed to have been moved to a hotel, is not linked in any way to the inquiry.

Detectives from the Met's anti-terror unit raided the flat, which is in a predominantly Asian suburb around two miles from Leeds city centre. Sources said the raid followed a tip-off from a member of the public.

Detective Assistant Commissioner John McDowall said: "While it is more than three years since the attacks, this remains a painstaking investigation, and as we have previously said we are determined to identify anyone else who knew what was being planned. As a result of our inquiries we are carrying out an extensive search of the flat to determine whether there are any links to the people responsible for the 7/7 attacks."

No one has been convicted over the London bombings, but three men from Beeston, Leeds, accused of helping to plan the bombings face re-trial early next year. The trial of Waheed Ali, Sadeer Saleem and Mohammed Shakil was abandoned in August after the jury failed to reach a verdict.