A senior Anglican academic is calling on the Church of England not to appoint any 'traditionalists' – those opposed to women priests – until a third of all bishops are women.

Warning the Church is damaging 'its public witness and Christian credibility' by promoting those who oppose female ordination, Prof Martyn Percy, Dean of Christ Church, Oxford, says the CofE 'needs to embrace equality unequivocally'.

Calling on the Archbishop of Canterbury to aim for 50 per cent female bishops in the next 20 years, he says the Church is 'the public's spiritual body and so needs to correspond to the very best standards in public life'.

In an essay published in Christian Today, Percy says conservatives who disagree with female bishops should, like pro-Apartheid groups in Nelson Mandela's South Africa, be protected but not given power.

'It could never be 'illiberal' to oppose the appointment of a pro-Apartheid politician as the new chief government minister for education. It would simply be rational to object to such an appointment,' he writes. 'There is no half-way house.'

It comes in response to a review published on Friday into abuse directed at the current Bishop of Burnley Philip North, who was forced to stand down from his appointment to be Bishop of Sheffield.

North, who comes from the Anglo-Catholic wing of the CofE and opposes women's ordination, pointed to the 'highly individualised nature of the attacks' against him which he said had been 'extremely hard to bear'.

But Percy said there 'is no case for entitling or privileging those who' oppose women's ordination.

'Minority views are protected and can be affirmed. But the will of this minority cannot be determinative for the majority,' he says.

'You may think what you like in private: but you can't implement such views and practices on the public.'

Using the analogy of the smoking ban he writes: 'It is not "illiberal" to regard "designated smoking zones" inside restaurants as anti-social. Nor is it "illiberal" to resist new requests for shared spaces being opened up for smokers, in order to compensate for their loss of old customary public places.'

He adds: 'In the same vein, a male bishop opposed to women priests will have a widespread impact on the 'air' of the whole diocese – clergy and laity alike – quite independent of any personal or public compensatory gestures they attempt to make.'

He adds: 'Gender equality is either equality, or it is nothing. Moreover, it is not 'illiberal' to oppose discrimination. The Church is not committed to accepting every shade of opinion as equally valid.'

When the CofE allowed women to become bishops in July 2014, it insisted the Church also 'remains committed to ensuring that those who cannot receive the ministry of women priests or bishops are able to flourish'. A compromise agreement was made, known as the 'five guiding principles', which allowed laws permitting women bishops to pass the CofE's synod but promised 'mutual flourishing' for those who opposed female ordination.

But when North, a traditionalist, was promoted to the senior role of Bishop of Sheffield in January 2017, the appointment was heavily criticised by Percy and a large number of women clergy in Sheffield.

Although senior figures came out strongly in support for North, with the Archbishop of York saying his promotion showed the Church allowed 'people who disagree on fundamental issues to continue to remain together', North eventually withdrew.

Percy's intervention in February was instrumental to North's decision to step down, a report published on Friday found.

Justifying his opposition to North's promotion and objection to the Church's 'mutual flourishing' principle, Percy said: 'The term "mutual" simply cannot mean that all convictions are equal, valid and valuable.'

Bishops were asked in the report to address the 'fundamental challenge' posed by Percy's argument against the 'five guiding principles' with Sir Philip Mawer, author of the report, telling Christian Today the questions posed 'can't just be glossed over'.

He said it was up to senior theologians to respond.

'Martyn Percy and others have raised fundamental issues which go to the heart of the settlement. Does that mean the settlement is up for questioning again? In my view, no. The Church has signed up to it and in fact it works. There are many more examples of success than failures.'