Probe into likelihood of further attacks

As they mount the third major investigation in a matter of weeks, the key priority for Britain’s counterterrorism agencies will be to establish whether any further attacks are imminent.

Police believe three terrorists carried out the atrocity and all have been “neutralised” after they were shot dead by armed officers.

Now detectives will be piecing together the backgrounds of the attackers as they examine whether they were part of a wider cell.

In the wake of both the recent Westminster and Manchester atrocities, police made a number of arrests and searched several properties. It is possible the same pattern will emerge in the coming days.

Investigators will also be scouring CCTV to build as comprehensive a picture as possible of the perpetrators’ movements in the lead up to the outrage at London Bridge.

Their electronic communications will come under scrutiny and assessing whether there is any connection to international groups will also form part of the probe.

Counter-terror police and MI5 will be working at pace to identify whether the three assailants plotted the attack alone – with their early theories forming a key plank of any decision regarding the official terror threat level.

It was raised to the most serious rating of critical in the days after the Manchester bombing, before returning to the second highest level of severe last weekend.

The assessment currently remains at severe – meaning an attack is “highly likely”.

This danger was brought into sharp focus by Prime Minister Theresa May yesterday. She said the three recent attacks are not connected in terms of their planning and execution but warned there is a “new trend” in the threat Britain faces.

The terror threat facing the UK is seen as unprecedented, with 18 plots foiled since 2013 – including five since the Westminster attack in March.