First Minister Alex Salmond yesterday announced plans to donate his Holyrood salary to a trust fund to help community projects in the north-east.

Mr Salmond, who is also the MP for Banff and Buchan, had come under increasing pressure to keep the promise he made before the Scottish Parliament election to accept only one salary if he was elected as the MSP for Gordon as well.

Under parliamentary rules, so-called "dual mandate" politicians must take their full MP's salary as well as one-third of their Holyrood entitlement.

But yesterday, Mr Salmond revealed that he had set up a special trust in the name of his late mother, Mary, to which he will donate £1474.75 a month - equivalent to one-third of his gross monthly MSP's wage - until he stands down as an MP at the next General Election.

The actual amount he will receive in his pay packet will be about £500 less than that after deductions but aides to the First Minister said yesterday he would make up the shortfall from his own pocket. His contributions will also be backdated to May 3.

Mr Salmond will, however, continue to claim his First Minister's salary of £76,907 a year which, when added to his £60,277 MP's salary, will give him a total income of £137,184.

The First Minister said: "I pledged that for the time I represent the north east as an MSP and as an MP that I would only personally benefit from one parliamentary salary, and not the one plus a third which the rules stipulate.

"By establishing this trust I am redeeming that commitment, and in so doing, allowing north-east community organisations to benefit."

Mr Salmond said he had named the trust the Mary Salmond Trust after his mother, who died at the age of 81 while hillwalking in the Highlands four years ago, because of her life-time supporting community organisations, particularly the Girl Guides. The trust will be run on a voluntary basis by Roderick McColl, a lawyer and oil company director, Harry Rankin, a chartered accountant, and Elizabeth Wallace, the managing director of Family Mediation Grampian.

It will support projects in the local authority areas of Aberdeenshire, Aberdeen and Moray and individuals and groups are able to make their own contributions.

However, applications from party political organisations will not be considered.

The Liberal Democrats have been particularly vociferous in their condemnation of Mr Salmond, claiming he had reneged on his pre-election promise by continuing to receive his one-third MSP's salary.

A senior aide to the First Minister insisted Mr Salmond had been in regular contact with the parliamentary authorities over how to honour his commitment and as a result had not received any of his MSP's salary until June 25.

The aide said: "This has been a complex process.

"There is no doubt that this is the best possible way to deliver on the pledge to his constituents and to maximise the public benefit."

The LibDems have also called on Mr Salmond to stand down as an MP, pointing out that he has not spoken at Westminster for more than 100 days.

But the First Minister's aide accused the Liberal Democrats of being "hypocritical, opportunistic and petty"

and said Mr Salmond will return to the House of Commons to speak in debates on Iraq or Prime Minister Gordon Brown's plans to make changes to the constitution.