Possible that 7/7 bombers widow involved in attack

The security source spoke on condition of anonymity.

Lewthwaite is the widow of Germaine Lindsay,one of the suicide bombers who killed more than 50 people on Londons transport system in 2005. She is thought to have left Britain several years ago.

In March last year,officials said she had fled to Somalia and that officers were hunting a woman who used several identities,including hers.

At a press conference in Pakistan,British Home Secretary Theresa May said: Im aware that there have been reports of a British woman being involved,but until we have seen the investigations completed it is not possible to give further details to confirm or deny that issue.