A senior Church of England bishop has told opponents of gay marriage they are like supporters of the former racist regime in South Africa.

The Rt Rev Nicholas Holtam, Bishop of Salisbury, has urged Christians to ‘rethink’ their attitude to homosexuality and change their interpretations of the Bible.

When speaking to members of UK’s House of Lords, Holtam explained allowing gay marriage would be a very strong move for the institution of marriage, the Daily Telegraph reports.

It comes as the House of Lords, the unelected upper chamber of the British parliament, prepares to debate the Marriage (Same Sex Couples) Bill for England and Wales next week. The bill has already been passed by elected politicians in the House of Commons.

In a letter he sent to gay Muslim peer Lord Waheed Alli, Holtam said he distanced himself from the church’s attitude to same-sex marriage saying: ‘Sometimes Christians have had to rethink the priorities of the gospel in light of experience.

‘For example, before William Wilberforce, Christians saw slavery as Biblical and part of the God-given ordering of creation.

‘Similarly in South Africa the Dutch Reformed Church supported apartheid because it was biblical and part of the God-given order of creation. No one now supports either slavery or apartheid.

‘The biblical texts have not changed, our interpretation has.’

The House of Lords has opposed the equal marriage bill approved by the House of Commons. There has also been speculation over whether the newly appointed Archbishop of Canterbury, Justin Welby, will be voicing opposition.

Alli asked Holtam to set out his views for the benefit of the house which will be debating the equal marriage bill next week.

Holtham added in the letter that gay marriage will not effect heterosexual marriage rights.

‘Indeed the development of marriage for same-sex couples is a very strong endorsement of the institution of marriage,’ he said.

Holtham was one of the first senior bishops to come out in favour of gay marriage in an interview he gave to The Times on 3 February.