Birmingham boss Alex McLeish believes his former club Rangers and Old Firm rivals Celtic would be credible contenders for the Barclays Premier League within three seasons if they were given the green light to enter the competition.

Having managed on both sides of the border, McLeish is in an ideal position to draw comparisons between the top teams from England and Scotland.

And he believes the Premier League's traditional big four would find their supremacy challenged if Rangers and Celtic migrated south.

"Both clubs are so massive that they would be competing for the title after two or three years," he told the Sunday Express.

"Maybe for the first couple of years they would have to find their feet, but because they have such a fanbase they would have powerful commercial revenue."

But despite his enthusiasm for the move, McLeish remains sceptical about its chances of getting off the ground.

"It would be phenomenal for the game if they were to play in the Premier League but it is a pipedream.

"I think UEFA, FIFA and everyone else would have to be in agreement and it would be difficult."