Revealed: Theresa May orders shake up of maritime border force, as police fear Afghan terrorists plotting attacks on London landmarks are on the run

An Isil-linked terror cell exploited migrant routes in to Europe to plot terror attacks on the UK, police fear, as Theresa May ordered a shake-up of Britain’s coastal defences.

The group photographed suspected targets in London, including hotels, restaurants and a health centre and may have planned to slip attackers in through Calais.

The alleged plot was unearthed after two Afghan men and a Pakistani man were arrested in Italy on Tuesday.

They had been granted refugee status in the country meaning they would have been able to take advantage of Europe’s open borders to move freely around the continent.

They are part of a suspected five-man cell, of which at least one was in London in December potentially scouting targets.