The widow of July 7 suicide bomber Mohammad Sidique Khan was among four people arrested today in connection with the attacks in 2005.
Hasina Patel, 29, was held with two men in West Yorkshire. A third man was arrested in Birmingham. The four, aged between 22 and 34, are suspected of commissioning, preparing or instigating acts of terrorism under the Terrorism Act 2000.
All four were taken to a central London police station where they will be interviewed by anti-terror officers.
Five houses in Dewsbury, Beeston, south Leeds and Batley and two flats in Birmingham were being searched.
Police said the arrests followed an intelligence-led operation involving the Met’s counter-terrorism command and units in West Yorkshire and the West Midlands. Armed officers were not used in today’s operations.
The two men held in West Yorkshire are aged 30 and 34. The man held in Birmingham is 22.
Officers said they did not believe any of the premises in West Yorkshire contained anything which could be a threat to the local community.
Fifty-two people were killed when four suicide bombers set off devices in three packed rush-hour London Tube trains and a crowded bus in 2005.
The bombers – Mohammed Sidique Khan, Shehzad Tanweer, Jermaine Lindsay and Hasib Hussain – all died in the attacks.
Last month, three men became the first people to appear in court charged with conspiring with the four terrorists.
Mohammed Shakil, 30, Sadeer Saleem, 26, and Waheed Ali, 23, from Beeston, Leeds, were arrested in March and appeared at the Old Bailey via video link on April 20.
Today in Beeston, police officers were patrolling the streets.
On Tempest Road, close to the family home of Aldgate bomber Shehzad Tanweer, an officer guarded the front door of an address while another stood guard in the back garden.
Next-door neighbour Carole Condon, 59, said an Asian family had lived at the address for a number of years. She said the family consisted of a mother and father, two brothers and a sister.
She said: “They were very quiet. I didn’t really know them but they would say hello. I don’t know their surname but they were always quite friendly. Their children would take the bins out into the back garden and I would say hello.”