The number among young Muslims aged 18-34 is even higher at one in four.

The figures emerged in our exclusive poll conducted after the Paris atrocities led by French and Belgian jihadis returning from the war zone.

Prominent Muslims said the poll was a wake-up call.

Labour London Mayor hopeful Sadiq Khan tells The Sun today: “It is clear that Britain needs to take its head out of the sand and act to tackle extremism and radicalisation at home.