Britain's interior minister Amber Rudd said on Tuesday a government report had concluded it was "conceivable" that security services could have prevented a suicide attack which killed 22 people at a pop concert in Manchester in May.

Salman Abedi, a 22-year-old Briton born to Libyan parents, blew himself up at the end of a show by US singer Ariana Grande in the deadliest militant attack in Britain for 12 years. His victims included seven children while more than 500 were injured.

Rudd said a government-commissioned report by David Anderson, the former independent reviewer of terrorism legislation, found security services were passed information on the suicide bomber earlier this year, but he was not considered high risk at the time of the attacks.

"It is conceivable that the attack might have been averted had the cards fallen differently,"