Banning the veil in schools led to Muslim girls getting better grades and more of them marrying outside their religion, a French study has found.

State schools in France were asked to ban “ostentatious religious signs” – including Islamic veils –   in 1994, but it was not forbidden by law until 2004. The ban came despite warnings from religious leaders that the law would persecute Muslims and encourage fundamentalism.

However, researchers in France have found that removing the veil in schools may have had some positive effects, including significantly improved educational outcomes for Muslim girls, as well as a rise in mixed marriages.

Prof Eric Maurin at the Paris School of Economics and a co-author of the study, said: “For students who wore the veil, the ban may have had a negative effect on those who were most attached to it, as it may have led them to drop out of school.

“But the ban may also have had a positive effect on students who were forced to wear the veil and on students suffering from stigmatisation and discrimination in school because of it.”

Muslim women born between 1971-74, who would have completed school before the 1994 ruling, were around 13 per cent less likely to graduate from high school than their non-Muslim peers.

This gap shrunk to just seven per cent among women born between 1987-90 who spent their education with some form of veil ban in place.

Prof Maurin, whose findings were presented at the 75th economic policy panel meeting earlier this month, added: “When comparing women in the Muslim group to those in the non-Muslim group, the data reveals a very significant increase in educational attainment in the Muslim group for the cohorts that attended middle school and reached puberty after the ban.

“This increase clearly coincides with the implementation of the circular: the more years the Muslim group women spent in middle school after the circular the higher their educational attainment.”

Marine Le Pen’s proposed veil blanket ban

The veil has become a hot French presidential campaign issue after National Rally candidate Marine Le Pen controversially announced she intended to impose a blanket ban of the headscarf in public – not just in schools and in the civil service – if elected on April 24.

“It’s an Islamist uniform that I would ban in public places”, she said last week, adding that women who failed to respect the ban would face fines equivalent to a “traffic offence”. It was, she insisted, “the uniform of an ideology, not a religion”.

Emmanuel Macron, 44, her rival and the incumbent, said such a move would violate French laïcité (secularism) safeguarding religious freedoms for all.

“There is no country in the world where the headscarf is banned in public. Do you want to be the first?,” he asked.

“Under the constitution, if she bans the veil, she’ll have to ban the kippa, the cross and other religious symbols,” he added.

Amid mounting criticism, Ms Le Pen has since rowed back on the proposal saying it is not a priority and anyway would be subject to parliamentary debate.