A woman using the name of the widow of one of the July 7 bombers is on a Kenyan police wanted list over a suspected terrorist cell planning bomb attacks.
A Nairobi official confirmed that a warrant had been issued for a woman using several identities, one of which is that of Samantha Lewthwaite, 28, who was married to King's Cross suicide attacker Jermaine Lindsay.
Scotland Yard said it had sent a team of officers to Kenya to assist authorities with a terror-related incident in recent months.
Kenyan officers believe Lewthwaite was most recently using the name Natalie Faye Webb and carrying a forged South African passport.
"I can give no details, but suffice it to say that we believe she is not a small fish,” a senior police source in Nairobi told the Daily Telegraph in January. “She is among several Britons that our intelligence service is aware of in relation to terrorists' plans to attack us."
Lewthwaite is believed to have evaded capture when authorities carried out a raid on a group suspected of planning a terror attack in Mombasa over Christmas.
Originally from Aylesbury, Buckinghamshire, Lewthwaite is reportedly travelling with her three children. She converted to Islam at the age of 15 and married Lindsay in 2002 before he killed 26 people when he blew himself up in July 2005.
The police spokesman in Nairobi said: "We do not know it is her (Lewthwaite)... we know she has (several) identities."
Police there are also said to be looking for another British woman, Habib Ghani, from Hounslow.
According to reports Ghani left Britain for Africa several years ago and is connect to Jermaine Grant, a Muslim convert from Newham who appeared in court in Kenya on charges of preparing a bomb for a terrorist attack.
The Metropolitan Police refused to discuss the extent of its involvement in the operation.