Michael Kelly, deposed as a Celtic director in 1994, said Mr Findlay's controversial rendition of a sectarian tune did not automatically make him a religious bigot.

"I know Donald and he's not a bigot," Mr Kelly told the Celtic magazine, Celtic View.

Mr Findlay was caught on video

He believes the thousands of Rangers and Celtic fans who sing sectarian songs from the football terraces each week would be embarrassed at being called bigots.

Mr Kelly added: "The story was that if you sing a sectarian song you are a bigot.

"I defend Donald - just because you sing a sectarian song does not mean you are a bigot."

Mr Findlay, one of Scotland's high-profile lawyers, was forced to resign as vice-chairman of Rangers earlier this year after being caught singing the anti-Catholic verse on videotape.

Mr Kelly's remarks have brought criticism from Celtic View Editor Joe Sullivan, who said they were "irresponsible."

However, the former Celtic director has found favour with Glasgow University's Dr Bert Moorhouse, an expert on the subject of sectarianism.

He said: "Whether the teams like it or not these traditional songs are part of the history of the club.

Celtic View's editor has condemned the remarks

"They don't, however, reflect the reality of living in Scotland where society is not divided on religious grounds.

"Catholics and Protestants work together, live together, are even married to one another without it being an issue.

"Yet these are the same people who sing these terrace songs."

Dr Moorhouse believes the rivalry between Celtic and Rangers is cultivated to make the Old Firm derby stand out above its English counterparts.

"There is a kind of imagined adversity because sectarianism in everyday life has decreased to a huge extent," said Dr Moorhouse.

Last week one of the UK's top composers, James MacMillan, used his Edinburgh Festival fringe address to attack what he said was a widespread prejudice towards Catholics in Scotland.