Most British Catholics now back abortion, according to a new census which shows a dramatic shift in Christians' social views.

For the first time a majority of Catholics – who typically hold to conservative views on issues of life and death – agreed 'the law should allow an abortion if the woman decides . . . she does not wish to have a child'.

It comes after Jacob Rees-Mogg, tipped to be a contender for leader of the Conservative Party, explained his staunch opposition to same-sex marriage and abortion by saying he followed the teachings of the Catholic Church.

The 2016 British Social Attitudes survey showed an increase in support for abortion among Catholics rise from 39 per cent when the question was last asked in 2012 in 61 per cent last year. The level of approval is only slightly lower than among those with no religion – 70 per cent of who back abortion according to the same survey.

The sudden rise comes after British Catholics views on abortion had remained relatively steady over the previous 30 years with the same poll in 1985 finding 33 per cent said a woman has a right to have an abortion.

In 1985 the proportion of those with no religion who backed abortion was 57 per cent after a significant shift in both the law and public perception following the 1967 Abortion Act that made termination permissible in certain circumstances.

The survey also found a majority of Anglicans saying gay relationships were 'not wrong at all' for the first time. The same study found a 50-50 split in 2015 with support among those of no religion at 76 per cent.

Meanwhile support for gay couples among Catholics continues to rise with 62 per cent backing same-sex relationships after crossing the 50 per cent marker in 2013.

However the official position of the Catholic Church remains resolutely opposed to both abortion and gay marriage and the Church of England has promised a more welcoming attitude to gay people but has offered no change to its stance against same-sex weddings.

Roger Harding, head of public attitudes at the National Centre for Social Research which carries out the British Social Attitudes study, said: 'We know from the British Social Attitudes survey that religious people are becoming more socially liberal on issues like same sex relationships and abortion. With falling numbers some faith leaders might wonder whether they should be doing more to take their congregation's lead on adapting to how society is changing.'