Walter Smith yesterday accused the Scottish Premier League of kowtowing to Celtic in the fixtures row and accused Peter Lawwell, the Parkhead club's chief executive, of acting disingenuously.

The Rangers manager has simmered since Tuesday's SPL decision to extend the league season by four days but only in the event of Rangers reaching the UEFA Cup final.

After steering the club to a 0-0 draw against Fiorentina in the first leg of their semi-final tie on Thursday, Smith ignited tomorrow's final Old Firm game of the season with a withering response to Lawwell's complaint that, by granting Rangers leeway, the SPL have "compromised the integrity of the competition".

Smith believes Celtic have benefited from the SPL's attempted appeasement and considers the Celtic chief executive to have been insincere in his intentions.

"The sporting integrity' situation has given me a good laugh," said Smith. "Peter Lawwell seems to be the head of the sporting integrity committee, as chairman and head spokesman.

"He would have been better saying Rangers should play four games in a week to suit his team and help their quest for the championship.

"If it was the other way, I would have been the same, but you are as well being honest rather than trying to hide behind the euphemism of sporting integrity'.

"He is doing the right thing for his club and for his own reasons, not for sporting integrity. He is as well being honest about it."

Smith was equally emphatic that Rangers have come off second best in the negotiations that resulted in the two final Old Firm games being played between a European semi-final and a Scottish Cup semi-final, won against St Johnstone last week.

It is understood Rangers have questioned the "integrity" of being forced to play their rescheduled game against Celtic on April 16, a game they lost 2-1, and not the game against St Mirren, that had been first in the backlog of postponed fixtures.

"The SPL have acceded to every request that has been made by Celtic and especially the placement of the two games we have at the moment," said Smith.

"It is no coincidence we have been asked to play two of the biggest league games when they Celtic would have a fair idea we would be playing them in between two very important semi-final games.

"The league had the option of playing these games at other times and in the end agreed to Celtic's request. Our own club have been treated unfairly in the placement of games.

"They SPL had a choice of where the fixtures could have been played - the two Celtic fixtures I mean - they had a choice of five alternatives."

While Martin Bain, the Rangers chief executive, had promoted the case for extending the season until May 27, Smith believes more modest flexibility would have been satisfactory. If Rangers reach the UEFA Cup final, the final league games of the season will be put back by four days from Sunday, May 18, to Thursday, May 22. Smith argues that in either scenario, Rangers' season should have been extended to the midweek before the cup final against Queen of the South.

He believes the unique Old Firm environment, fuelled by conspiracy and paranoia, has forced the SPL's hand. In short, this kind of furore could only happen in Scottish football.

"Aye, possibly," said Smith wearily. "If you think about it, no other country has teams that are so aware of offending one side over the other. It definitely influences their decision.

"Normally, this kind of thing I would not get involved in, but in this instance it has a direct effect on my own job, in terms of what we have ahead of us. After reading the stuff put out by the SPL after their judgment, the fact is they haven't really taken any decision in the sense that it is physically impossible for us to play all the league games we have left.

"Actually, they had no alternative but to extend the season if Rangers reach the UEFA Cup final.

"What they have done in the other scenario is put us in a situation where we could play four games in a week. We accept it, but is it right from the league's point of view to force a club to do that? From Rangers' point of view, the league have opted out of a decision to help a club who, in many ways, have helped to lift the profile of Scottish football."

Smith will now attempt to patch up his side for an uncompromising climax to the season. "To me, it is reasonably simple to extend the season but maybe I'm a bit naive," he said. "If the SPL thinks that's the way to treat their teams, then no problem, but it can impact on your job and how people look at your job. It will be manageable because it will have to be."

Gordon Strachan, the Celtic manager, refused to get embroiled in a war of words, saying only: "We've made a statement and, as a manager, I will play when I'm told to play. I was like that as a player. you play Saturday, Wednesday, Sunday, you get on with it."