More Isis fighters have returned to UK than any other country in Europe

More Islamic State fighters have returned to the UK than any other country in the West, according to MI6’s former director of global counterterrorism.

Richard Barrett’s report for the US-based Soufan Centre think-tank states that more than 425 of the 850 Britons who left to join the Islamic State of Iraq and the Levant (Isil) in the last five years have returned, only fewer than Turkey's 900 returnees, Tunisia's 800 and Saudi Arabia's 760.

Germany has seen around 300 return, while France - which saw nearly 2,000 join Isil - has 271 returnees, the Telegraph reports.

The report also reveals that more than 1,100 high-risk Britons have been flagged to authorities in Turkey over suspicions that they planned to travel through the country on to neighbouring Syria. 

In total, in excess of 40,000 individuals have travelled to join Isil from more than 110 nations both before and after it declared a caliphate in June 2014.

Comments from international development minister Rory Stewart suggested that the only way of dealing with Isil is to kill it  "in almost every case".

However, Mr Barrett doesn’t believe these sort of comments are helpful.

“They won’t do much to encourage those looking to surrender or give up their fight to do so. They will probably decide they’re better off just battling to the end in that case,” he told the Telegraph.

“It will only feed conspiracy theories that they already believe that our special forces are just killing them all on sight and there is no judicial process.”