Allied strike kills Jihadi John

His remarks outside Downing Street were in reaction to news that US forces had carried out an air strike targeting Islamic State group militant Mohammed Emwazi, known as “Jihadi John”, the Kuwaiti-born British militant.

A senior military source told the BBC there was a “high degree of certainty” he had been killed.

David Cameron emphasised it was an act of self-defence against an individual who had assassinated aid-workers.

The attack was a reminder that the US and Britain “have a long reach” and that both countries do not forget attacks on their citizens, he said.