Scotland's top soldier yesterday contradicted Tony Blair's claim that the future of Scotland's regiments lies with the Army and urged ministers to make a decision soon to stop ''this terribly corrosive'' debate.

The prime minister said last week that it was up to the Army to make the vital decision on whether Scotland's six regiments are merged into a single large regiment with one less battalion.

But Major General Ewan Loudon, the general officer commanding (GOC) for Scotland and the north of England, speaking on BBC Scotland yesterday, said it was for the Army to advise and ministers to decide.

''I assume this is a decision for ministers and I would like to see it resolved as quickly as possible so that we can put the corrosive aspects of the debate that have been very much in the public domain over the past few months and get on with it.

''The service chiefs are given a certain amount of resource to provide the best possible defence capabilities they can, and when a change like this, which is enormously painful, is going to be driven through, the service chiefs will give their advice to ministers and ministers will make their decision based on that.''

He also argued the case for change, saying the regimental system has the virtue of having strong regional identities and loyalties, but there were problems of being too inflexible.

And he said the reform would cut down substantially on the amount of changing of location and role which Army units undergo, which means that, of 40 units, as few as 26 are available at any time.

The government will come under fresh fire on Wednesday when MPs debate the regimental shake-up plans. Pete Wishart, the SNP MP for North Tayside, will lead the debate in Westminster Hall, the parallel chamber to the Commons. Veterans from the Black Watch and other Scottish regiments are expected to lobby parliament.

Tony Blair has insisted the decision on the structure of the Army will be ''military-led''. But he is fully appreciative of the sensitivities in Scotland of scrapping the regiments, particularly when Black Watch soldiers are in action in Iraq.

Geoff Hoon, defence secretary, insisted to David Dimbleby on TV that it was his ''ambition'' to retain the identity of the Black Watch, but failed to explain exactly what he meant.

Stressing the decision had to be military-led, he added: ''Certainly, it is within a very reasonable probability that formula - that you have described, where the name of a historic regiment is part of its ultimate title - is something that is a proper solution to this issue.''