A Scottish businessman notorious for his anti-gay views has donated £500,000 to the Scottish National Party.

Brian Souter, a self-made millionaire and devout Christian, was revealed as a party donor on Saturday.

In 2000 Mr Souter gave over a million pounds to a campaign in Scotland to uphold Section 28, which banned the promotion of homosexuality in schools.

He cited his religious beliefs as justification for his actions, insisting he is not homophobic.

However, gay rights advocates have reacted strongly to the news that Mr Souter is backing the nationalists.

In the elections for the Scottish parliament this May the ruling Labour party are expected to suffer losses to the SNP.

“The SNP would never accept a donation from an avowed racist, so why are they accepting funding from a man who is clearly homophobic?” commented Peter Tatchell, of gay pressure group OutRage!

“Accepting this tainted money is an outrageous insult to every gay person in Scotland and to everyone who loves and respects human rights.”

Mr Souter is a member of the Church of the Nazarene, a Methodist denomination.

His Stagecoach Group bus and train operating company is the second-largest in the UK with 16% of the bus market and 11% of the rail market.

In 2000, he funded a “poll” of Scottish voters, sending out nearly four million ballot papers on the repeal of Section 28. The campaign failed in its objective.

A spokesman for Stonewall Scotland did not comment on Mr Souter or the SNP, but did say:

“Regardless of who any political party accept donations from, they have a duty to the 400,000 lesbian and gay Scottish voters to let them know where they stand on LGBT equality.”

In the row over gay adoption, the SNP at first voted to allow gay couples to adopt, then appeared to back an opt-out for Roman Catholic-run adoption agencies from the new law.

Mr Souter is well-known for his nationalist views, and his high-profile donation to the SNP follows last week’s announcementn by the Royal Bank of Scotland chairman Sir George Mathewson that he is supporting the SNP.

Gay MSP Patrick Harvie, from the Green party, told the BBC: “I call on all parties standing in the Scottish election to disassociate themselves from homophobic prejudice such as Mr Souter’s former political enterprise.

“It is essential that serious politicians avoid any taint of pandering to bigotry, whether that be racial, religious, homophobic or any other kind.”