Last year, Abu Mohammed al-Adnani, the late Isil spokesman, issued a call to arms to followers to carry out lone wolf attacks during the holy month. Hundreds went on to die in attacks linked to the group.

Mr Orton said it was difficult to attribute attacks to individual messages, but said there was a “real major uptick in these attacks over Ramadan”.

He said: “In Britain in particular there’s been among Isil and their fans and supporters a significant mention of Britain as a target in these recent weeks. I don’t know if that has led or followed the attacks here.”

Telegram, an increasingly popular secure messaging service, has become the channel of choice for Isil propaganda, he said.

Isil’s loss of territory and the dwindling number of foreigners making the journey to join the group’s self-styled caliphate may have also contributed to the growing number of attacks in Europe, he suggested. The international coalition fighting Isil has said that at one point as many as 1,000 foreigners were travelling to the caliphate each month. That has now fallen to a “handful” it says.