Leaders representing more than a million British ethnic minority churchgoers have called for a referendum on equal marriage.

Reverend Yemi Adedeji, director of the One People Commission, a grouping of 6,000 primarily ethnic minority congregations whose churches claim at least a million members, is among the signatures.

Rev Adedeji said David Cameron’s vision of equality appeared to be that of a “white, liberal elite”.

The letter is also signed by the South Asian Forum, a network of Asian UK churches, and the New Testament Church of God – a network of churches predominantly for the black community.

In an open letter to the Telegraph, the leaders said:

The government is forcing through fundamental changes to the nature of marriage, and has failed to think through the consequences properly. We are leaders of large, ethnically diverse denominations in Britain – growing churches. Instead of hearing our concerns, the government is taking direction from tiny faith groups to infer backing for its plans.

If the government gets its way, it will not be a victory for equality. Equality requires diversity, and diversity requires distinctiveness, and marriage is and always will be distinctively a union between a man and a woman. By changing marriage from its historic foundation it would be creating a legal fiction, and consequently devaluing this vitally important social institution. The government is not respecting difference, and it is not promoting a plural society.

The people of Britain need to have their say. These plans were not in any party’s manifesto, and if the government had any respect for democracy it would allow a referendum before making fundamental changes to the nature of marriage.

With the Commons committee stage of the Marriage (Same Sex Couples) Bill now complete, the House of Lords is set to debate the bill in May.

In January, Conservative MP Mark Pritchard called on his party to “shelve” the bill, claiming it was unlikely to attract the votes of ethnic minorities.