Tony Blair has accused the Conservative leader of "shabby opportunism" during clashes over the future of Scottish regiments.

Michael Howard accused the prime minister of undermining the Black Watch regiment, which is currently fighting in Iraq, for refusing to confirm that plans to merge Scottish regiments had been scrapped.

In exchanges during prime minister's question time, Howard said: "Why can't he confirm he is reversing the policy of scrapping the Scottish regiments?

"The way this is being handled when Black Watch soldiers are fighting in the field is a shambles.

"The defence secretary has said the Scottish regiments will be abolished while the prime minister is briefing the Scottish newspapers that the plan is dead."

"Doesn't the prime minister understand it is quite shameful to treat soldiers and their families in this way?" Howard added.

An angered prime minister said he was "surprised" by his opponent's attitude.

"No one has announced that the regiments will be abolished," he told MPs.

"I fully understand the concerns people have about this but the Army are carrying out their review, no decisions have been made and I regret that his comments are nothing but shabby opportunism."

Reports

The clash followed reports in Scottish newspapers that proposals to merge the Scottish regiments had been quashed.

Campaigners reacted with caution to the reports that would mean the majority of Scotland's infantry regiments would be saved.

Ministers have been under pressure over a possible decision to merge the six Scottish regiments into one unit.

The uncertainty has caused anger among Black Watch families and others, with the regiment facing the possibility of being disbanded while engaged in difficult operations in central Iraq.

But Labour backbencher Eric Joyce has suggested the merger of the Royal Scots and the King's Own Scottish Borderers as part of a scheme that would see the other regiments retain their identity.

Number 10 refused to say whether the plan enjoyed the prime minister's support.

"A review is going on and any decision will be taken on military advice," the spokesman said.

Joyce, the MP for Falkirk West, said he had "simply put a few arguments among colleagues and put it up to people in government".

"I think the government is prepared to listen to backbenchers and I probably represent the common view among my Labour colleagues," he suggested.

The Save the Scottish Regiments campaign group said it was "very cautious about this latest development".

"We must have 100 per cent confirmation and guarantees that this is in fact a u-turn before any slow-down in our campaign," said a statement.

"The campaign set-out to save all six Scottish regiments and not just two-thirds. The Kings Own Scottish Borderers and the Royal Scots are still due for a merger and this remains unacceptable."

Also commenting on the reports, Liberal Democrat spokesman Sir Menzies Campbell said it was possible that common sense would now prevail.

But he warned that "we will have to see the precise details before reaching a final conclusion".

SNP leader Alex Salmond said signs the government was "buckling under pressure" were to be welcomed.

"We have a situation where feelings are running high about the war and the deployment of the Black Watch who are being stabbed in the back and merged out of existence while they stand in the line of fire," he said.