.... In the wake of the Manchester suicide bombing it emerged that the authorities were grappling with 500 investigations into 3,000 individuals.
Figures published in May suggested that a further 20,000 individuals had been considered "subjects of interest" in the past, although the period the figures cover is unclear.
Anti-terror efforts came under fresh scrutiny following revelations that suicide bomber Salman Abedi had been a "former subject of interest" to MI5 who was "subject to review".
Security minister Ben Wallace said at the time: "All those people are in the mix and they have to be looked at."
A senior Whitehall source said 18 plots had been foiled since 2013 in Britain, including five since the Westminster atrocity in March this year. [The Telegraph] Read more
