The SPL chief executive, Lex Gold, admitted on announcing two different schedules – each designed to accommodate Rangers' fate in the Uefa Cup – that he had already been assailed by dissidents from all quarters over the plans, but he could not have been prepared for the savagery of Bain's outburst.

Lawwell's follow-up, questioning the decision-making process and claiming that the integrity of the competition had been compromised, merely underlined the impossibility of satisfying all parties with any attempt to clear up the clutter.

Ibrox chairman Sir David Murray's first lieutenant railed against both SPL "models", one of which allows a four-day extension to the season in the event of Rangers reaching the European final on 14 May, the alternative ordering that the league programme be completed as originally designated on 18 May.

Bain took issue with the possibility of Rangers having to play league games on the Sunday, Wednesday and Saturday in the week preceding the Uefa Cup final, claiming that the SPL "are doing nothing to assist us". This seems to take no cognisance of the fact that the only reason for the two "models" is an attempt to accommodate the Ibrox club's complicated commitments.

"We as a club are bitterly disappointed with the SPL on all fronts," said Bain. "It is hardly the best preparation in the lead-up to the Uefa Cup final – if we get there – to play Sunday, Wednesday, Saturday in advance of that. So I don't see what the SPL have done for Rangers in terms of aiding them in European competition. They have simply accommodated a fixture. As for the situation of not being in the Uefa Cup final, we have been asked to play four games in eight days (at the end of the season).

"The SPL cite the preservation of sporting integrity in their decision, yet Rangers are the only club being asked to play four games in eight days, so there is no sporting integrity. What we find baffling is that the SPL can extend the season if we reach the Uefa Cup final but can't do it from a sporting integrity point of view if we don't. Why is the season not simply extended to conclude on 27 May regardless?"

Lawwell, unsurprisingly, took the view that Celtic and the other clubs in the top half of the league had been seriously inconvenienced. "We do not want to disadvantage Rangers should they reach the UEFA Cup final," he said, "but we are extremely disappointed and concerned at the manner of the decision-making process which was done without consulting the clubs or the SPL board and the effects on the integrity of the competition.

"In addition, this decision, which will cause a great deal of inconvenience to our supporters and to five other clubs, will also mean that Celtic would have a gap of 11 days before playing our final league fixture. A number of our key first-team players are also due to go on international duty immediately after our scheduled final league game on Sunday, 18 May.

"In principle we accept fixture flexibility. However, the league must not be compromised by changing the rules during the course of the competition and these decisions should not be made on an ad hoc basis."

The first template, to be adopted if Rangers fail to overcome Fiorentina in the semi-final of the European tournament, would see the league programme end on the originally scheduled date, Sunday, 18 May.

The second, which will take effect if Rangers qualify for the Uefa Cup final, will bring a four-day add-on, with the last round of fixtures, involving only the top six in the league, taking place on Thursday, 22 May.

Whichever applies, Rangers will face four matches in eight days at the end of their schedule. Without the European commitment, they will have four league games between 10 and 18 May, while the alternative will ensure, between 17 and 24 May, three league fixtures and the Scottish Cup final, the latter to be faced less than 48 hours after their last league game at Aberdeen.

"Many people will take the view that we are favouring Rangers, while Rangers themselves may think the extension is not long enough," said Gold.

"I'd expect Rangers to be unhappy that the extension will not be longer than four days, but if we arranged games beyond the Scottish Cup final, we'd have had teams in the top six waiting at least 17 days for a game.

"It was our decision, made by myself and Ian Blair, our secretary. The board leave fixtures matters to Iain and, in the event of complications such as now, he comes to me. I'm sure there will be members of our own board who aren't happy with it.

"It's inevitable this kind of action won't be to everybody's satisfaction. But the most difficult part was to try to uphold the integrity of the competition and to be fair to clubs and supporters."

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