Security services believe they have foiled a plot to assassinate Theresa May in Downing Street.

Two men have been arrested on suspicion of plotting to kill the Prime Minister by using a bomb disguised as a bag to blow off the gates of Downing Street and then attack her with knives.

The suspects were detained during raids in London and Birmingham last week and charged with terrorism offences. They are due to appear in Westminster Magistrates' Court on Wednesday.

The plot was revealed to the Cabinet yesterday by Andrew Parker, the head of MI5.

Mr Parker also told ministers that security services have foiled nine terrorist attacks in the last year.

The Metropolitan Police said 20-year-old Naa’imur Zakariyah Rahman, from north London, and a 21-year-old Mohammed Aqib Imran, from Birmingham, had been charged with preparing a terrorist act.

A Scotland Yard spokesperson declined to confirm that the arrests were linked to a plot to attack Ms May.

It comes as a new report found that security services could have prevented a suicide attack at the Manchester Arena in May. Bomber Salman Abedi killed 22 people when he blew himself up outside an Ariana Grande concert.

Dave Anderson QC, who was asked to conduct an independent study, said Abedi had been MI5's radar but that his "true significance was not appreciated at the time".

After reviewing the security services' actions in relation to four terrorist attacks in the UK this year, Mr Anderson said: "It is conceivable that the Manchester attack in particular might have been averted had the cards fallen differently.”

Independent News Service