A new analysis of the 2011 census shows that a decade of mass immigration helped mask the scale of decline in Christian affiliation among the British-born population – while driving a dramatic increase in Islam, particularly among the young.

It suggests that only a minority of people will describe themselves as Christians within the next decade, for first time.

Meanwhile almost one in 10 under 25s in Britain is now a Muslim.

The proportion of young people who describe themselves as even nominal Christians has dropped below half for the first time.