Catholics are bracing themselves for a government U-turn that would block new Catholic faith schools from opening, Christian Today understands.

Ministers are preparing to backtrack on a manifesto commitment to remove the 50 per cent cap on free schools admitting pupils on the basis of religion. In another sign of Theresa May's weak hold on power officials are 'laying the groundwork for a U-turn' that would effectively be a 'form of Catholic discrimination', a senior source in Parliament told Christian Today.

Although Theresa May and government officials are thought to be in favour of removing the restriction, the Education Secretary Justine Greening is understood to be personally opposed to allowing faith schools to select pupils on the basis of faith.

Another source said Greening is 'throwing her weight around' and using the Prime Minister's weakness to rescind on a manifesto promise. 

While humanist campaigners say the current laws prevent discrimination and promote diversity by forcing all new faith schools to award half of places irrespective of faith, the Catholic Education Service says it effectively means Catholic pupils are turned away from Catholic schools simply because they are Catholic.

It breaks the Church's Canon Law to refuse a Catholic pupil a school place on the basis of their faith and so no new Catholic schools have been opened since the cap came into force under the Tory-Lib Dem coalition government.

After the Conservatives won the election a number of Catholic dioceses invested thousands of pounds in plans for new schools on the basis of the manifesto promise and are now being forced to pause those projects as the threat of a U-turn grows.

The Prime Minister is now coming under pressure from her own backbenchers to implement the policy with the Department for Education refusing to answer whether it still supported removing the cap.

Sir Edward Leigh, Tory MP for Gainsborough and a leading figure in favour of the change, told Christian Today the 'cap has failed in its objectives and its only significant effect now is to act as a barrier to the creation of Catholic free schools'.

He said: 'The Prime Minister was right to announce that it would be scrapped accordingly, and we included it in our Conservative manifesto during the general election campaign. We have been encouraging the Education Secretary to enact this as soon as possible so that the Catholic dioceses which have invested tens of thousands into planning for new schools can get on with their work.

'There is a shortage of Catholic school places and this needs to be alleviated as soon as possible.'

Catholic bishops have launched a campaign to pressurise Greening to follow through on removing the cap, which would not require a vote in Parliament.

A petition, backed by the head of the Catholic Church in England Wales Cardinal Vincent Nichols, aims at convincing Greening to implement the policy, pointing out she previously admitted the current 'rule has been ineffective and adversely affects Catholic families'.

Most Rev Malcolm McMahon, Archbishop of Liverpool, said: 'The Bishops of England and Wales are resolved that the presence of the admissions cap is not a secure basis for founding of Catholic schools.

'Being Catholic should never be a barrier to getting into a Catholic school. We'd be failing our young if our community was to let this happen.

'That's why we're urging all Catholics and those who support the principle of parental choice to write to the Secretary of State for Education, to tell her about the strength of feeling on this issue.'

The petition launched by the Catholic Bishops Conference of England and Wales reads: 'By forcing Catholic schools to turn away Catholic school children on the basis of their faith, the very principle of a Catholic parent's right to choose a Catholic education is under threat.'

A spokeswoman for the Department for Education told Christian Today ministers would make an announcement on faith schools in due course but gave no indication of a timescale.