Ally McCoist last night denounced the criticism and conspiracy theories surrounding the omission of four Rangers players from Scotland duty through injuries that will not prevent their participation in today's Old Firm derby at Ibrox.

The Rangers assistant manager was also angered by accusations of hypocrisy levelled at Walter Smith, a former Scotland manager, over international availability.

McCoist insisted that Barry Ferguson, Christian Dailly, Allan McGregor and Lee McCulloch were removed from the Scotland squad on genuine medical grounds after being assessed by Professor Stewart Hillis and Dr John MacLean, the Scotland medical team.

McCoist admitted all four are available for selection for today's derby but is astonished that the doctors' integrity has been called into question, especially after fresh claims that Barry Robson, the Celtic midfielder, was removed from the squad against his will.

"Any attack on Walter Smith is laughable," said McCoist. "Maybe there has been cynicism in some quarters but not here. Nobody knows both sides of the fence, both angles of club and international football, better than Walter Smith. He knows how important it is for the club to be represented internationally and knows the situation of the players, the Scotland manager and the SFA.

"I think everybody is missing the fact that the medical boys had a look at them and deemed them not to be fit enough to play. Two or three days can be an awful long time in terms of recovery and I would be disappointed if all four are not fit and available for selection.

"It is unfair in the respect that the medical staff assessed the players. There will always be people saying this or that about it but the fact is they were carrying injuries and I can assure you that is a fact."

McCoist arrived at yesterday's media conference with his right hand heavily bandaged. A renowned prankster in his playing days, he was quick to assure that the strapping was a result of a recent operation to a hand injury and not a comedy prop.

He rejected the notion that the quartet of players had conveniently dropped out of the 1-1 draw against Croatia on Wednesday to prepare fully for today's derby and, amid claims of disloyalty, McCoist recalled the broken leg sustained against Portugal in 1993 that kept him out of action for a year.

"Whether they would have played if it was a World Cup qualifier we will never know," he said. "Christian fractured his wee toe, which is very painful, and Barry did receive an injection. It is very seldom any player is 100% fit at this stage of the season.

"Nobody is in a position to pick and choose when they want to play for Scotland. The point is these guys were unfit to do so. People should not forget, either, that I was out for a year after breaking my leg playing for my country. That is part of the territory. It is naive to question the players' dedication. Most guys have never played in a major championships and that can be the highlight of your career."