Tory right-wingers Chris Grayling and Baroness Sayeeda Warsi have said that they will vote in favour of allowing same-sex couples to marry next week.

Both ministers have a checkered history when it comes to gay rights but are both ministers with portfolios that would make it extremely hard to oppose the measure proposed by David Cameron and Nick Clegg.

Mr Grayling is Justice Secretary while Baroness Warsi is Minister for Faith and Communities as well as a minister of state at the Foreign Office.

Same-sex couples in England and Wales are set to be allowed to marry, under plans announced by Culture Secretary Maria Miller in the House of Commons last year.

Later, Baroness Warsi wrote to Mrs Miller and asked her: “What legal support will be afforded to churches and other places of worship if they’re challenged individually or as an organisation?” She added: “What consideration has been given to the teaching of equal marriage in schools, both faith schools and non-faith schools?”

It appears that Mrs Miller adequately answered Baroness Warsi’s questions, as she has said that she will support the bill.

In 2005, when she unsuccessfully stood as the Tory candidate for Dewsbury, Baroness Warsi issued leaflets which used homophobic language.

Her leaflets claimed children were being “propositioned” for gay relationships.

They said: “Labour has scrapped Section 28, which was introduced by the Conservatives to stop schools promoting alternative sexual lifestyles such as homosexuality to children as young as seven years old.

“Labour reduced the age of consent for homosexuality from 18 to 16, allowing schoolchildren to be propositioned for homosexual relationships.”

Baroness Warsi later said she regretted the language used.

Mr Grayling became embroiled in a storm of controversy in the spring of 2010, after he suggested that it was acceptable for Christian hoteliers to discriminate against same-sex couples.

One of the Labour MPs to shadow Mr Grayling, Rob Flello, has said that he will vote against introducing same-sex marriage due to his religious convictions.