MI5 missed chance to foil Paris and Brussels terrorists

Undercover operation was halted three months before meeting between ringleader and British extremists

Police and MI5 could have prevented the Paris and Brussels terrorist atrocities after a secret operation targeting British suspects linked to the plot was launched months before the attacks.

But senior officers decided to halt the undercover probe three months before one of the coordinators of the Paris attacks crossed the Channel to meet extremists in Britain, it can now be disclosed.

The decision meant that investigators missed a key meeting between a group of alleged Islamic State supporters in Britain and Mohamed Abrini last summer – which could have led them to the Brussels-based cell before they carried out a wave of shootings and bombings, killing 130 people in Paris last November.