Holyrood's standards watchdog today dismissed claims that Alex Salmond and Nicola Sturgeon broke rules governing MSPs' behaviour after lunches with the two top politicians were auctioned to raise cash for the SNP.

Labour had asked Scottish Parliamentary Standards Commissioner Stuart Allan to investigate the matter and establish if the MSPs' code of conduct was broken.

The auction, where lunches with the First Minister and Deputy First Minister were sold for a total of £11,000, sparked a furious row at Holyrood. But in a letter to Mr Salmond and Ms Sturgeon, the Commissioner said there was "no evidence of sufficient substance warranting further investigation" and dismissed the complaints.

A spokeswoman for Mr Salmond and Ms Sturgeon said they had been "comprehensively cleared on all counts before the Standards Commissioner".

She added: "This is a humiliation for the Labour Party and the disreputable campaign which they orchestrated. The Commissioner's decision is hugely welcome, a devastating dismissal of Labour's put-up job, and a victory for common sense."

The lunches, which were to have taken place in the Scottish Parliament restaurant, were cancelled after the row over "cash for access" to the First Minister and his deputy erupted.

Mr Salmond has already said that no monies had been received up-front from the auction winners.

The Commissioner had been asked to investigate whether the two politicians breached the part of the code which states MSPs should not take part in any event if they are aware "that the organisers are promoting the event on the basis that those paying to attend the event are buying influence over MSPs".

Mr Allan dismissed this, saying there was "no evidence the bidders were lobbying or seeking improper access" to either Mr Salmond or Ms Sturgeon.

In considering whether the lunches breached the part of the code on registration of interests, the Commissioner stated: "There are no gifts as - quite simply - the donations have not been made and there is nothing to register."