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 Ms Lewthwaite was most recently using the name Natalie Faye Webb and carrying a forged South African passport.
She 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.
Ms Lewthwaite, originally from Aylesbury, Buckinghamshire, 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 (Ms Lewthwaite)... we know she has (several) identities."
The Metropolitan Police refused to discuss the extent of its involvement in the operation.
