THE CAMPAIGN to retain the names and badges of Scotland's historic regiments received a major boost from the Prime Minister last night.

It has emerged David Cameron has let it be known within Whitehall that he is not personally convinced scrapping any of them would be a good idea either militarily or politically.

The row over the possible threat to traditional names like the Black Watch continued yesterday when Philip Hammond, the UK Defence Secretary, insisted replacing names with numbers was not an option.

However, he failed to say whether all historic regimental names in Scotland would be retained.

In the Commons, Labour's Jim Murphy insisted Scottish military tradition could not be cast aside.

He asked the Secretary of State to reassure people the traditional names, identities and cap badges would be retained.

"Failure to do so," he declared, "will show yet again that this is a Government totally out of touch with Scotland."

Mr Hammond insisted he had no intention of introducing a "continental-style army", with numbers replacing names.

Angus Robertson for the SNP asked whether the Secretary of State could "rule out the prospect of any further amalgamation or disbandment of Scottish-raised units".

Mr Hammond insisted the defence of Scotland did not just happen in the country itself but under the oceans and in places like Afghanistan and then added: "I will tell him frankly: we are going to have a smaller army.

"You can't have a smaller army without some structural changes."

This lack of reassurance later led Mr Murphy to say: "The Secretary of State's response was totally inadequate.

"He seems to be in denial about the strength of feeling in Scotland."

Mr Robertson, the Nationalists' defence spokesman at Westminster, added: "Philip Hammond's refusal to rule out further amalgamation or disbandment of Scottish-raised units is a further betrayal of promises by the Tories when they were in opposition that they would reinstate Scottish army units."

The SNP has pledged to reinstate any historic name that is lost.

However, Coalition sources indicated the prospect of any historic Scottish regimental name being scrapped had diminished markedly because of the Prime Minister's intervention.

Last week, it was suggested Mr Cameron had taken a "personal interest" in the issue after a warning from Ruth Davidson, the Scottish Conservative leader, that losing any traditional name could have a disastrous effect on the pro-UK referendum campaign.

Last night, one Coalition source told The Herald: "The PM is not convinced by the idea that the names of the historic regiments should be scrapped in Scotland."

As Mr Hammond mulls over the options, it was suggested Michael Moore, the Scottish Secretary, had become "seriously engaged" in trying to retain the Scottish regimental names.

One option being talked about is that if one or two regular Scots battalions were cut, their historic names and badges could be given to Scotland's two TA battalions.

Another senior Coalition source said: "People are conscious that the golden thread of tradition still matters.

"The Prime Minister is taking an interest in this but no final decision has been made yet."

He added: "We are determined to get this right and not rush to answer the scaremongers."

A decision on how the Army numbers will be cut is due before Westminster's July recess.