A bitter war of words broke out last night between the chairmen of Scotland's two biggest football clubs as the controversy over a song sung by Rangers fans escalated.

John Reid, the chairman of Celtic and a former minister in Tony Blair's Government, hit back after Sir David Murray, his counterpart at Rangers, told him to be more careful with his public condemnation of “the Famine song”. The song, which includes the line, “The famine's over, why don't you go home?”, refers to the Irish Famine in the 1840s, which is estimated to have killed one million people and led to mass migration. Many of the migrants moved to Scotland.

Mr Reid, the former Northern Ireland Minister, who has described the song as racist, responded last night to Sir David's criticism of him by saying: “I will continue to comment, when appropriate, without fear or favour.”

Sir David, in an interview with The Times, had said that there was “an unwritten rule” among Old Firm chairmen that they did not criticise the other club.

He added: “I find it has changed since John Reid came in. John has taken a few shots at us. He has to remember he is not in the House of Commons now, haggling across the chamber. We are in the west of Scotland. This is the world of Rangers and Celtic, and I think we all have a responsibility to act sensibly.”

Sir David, who gave the interview to mark his twentieth season in charge at Ibrox, expressed concern at “some of the innuendo” that has come from Mr Reid. The Rangers chairman, who bought the club for £6million in 1988, urged his Celtic counterpart, who became chairman of the club last year after leaving the Government, to be more careful with his comments.

“I find it strange that a man could become a member of Parliament representing a whole broad church of people from Airdrie and Shotts, but then can also be the chairman of a football club and come out with a different slant,” Mr Murray said.

“I suppose he can say that because he knows he doesn't have to be re-elected to Airdrie and Shotts again [Mr Reid is standing down as an MP at the next election]. I'm concerned by some of the comments.

“I give the utmost respect to Celtic football club - they've got a great tradition - but I am a wee bit concerned by some of the inferences and innuendo that's come from John and I think he's got to be careful and realise he's not barracking in the House of Commons any longer.

“We are in a society in Scotland where every point and every word is picked up by everybody and he should be very careful with some of the chat.”

Mr Reid said: “We all want to be a little indulgent to David on his twentieth anniversary, but I'm not entirely sure of the points he is trying to make regarding inference and innuendo.

“In any case, no one should be under any illusion that in defending the welfare of Celtic and our supporters I will continue to comment when appropriate, without fear or favour.

“I know we all welcome David's respect for Celtic's traditions and we congratulate him on 20 years at Rangers football club.”

After Sir David bought Rangers, the club won nine championships in a row between 1989 and 1997. He stepped down as chairman in July 2002 but returned to the post two years later.

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