SNP ministers have been urged to stop an “outrageous” whitewashing of the political record as Scotland’s information watchdog appears before MSPs.

The LibDems highlighted a row over civil servants being ordered to immediately delete emails from political advisers about freedom of information (FoI) requests.

The practice was uncovered by investigative writer James McEnaney, who obtained the rules for officials handling input from special advisers (SpAds) on FoI.

These included the instruction: “Once SpAds have provided final comments on the request keep only the email containing the final comments and the final response letter. Delete everything else immediately."

Holyrood’s public audit committee will today hear Scottish Information Commissioner Daren Fitzhenry, who is investigating the government’s FoI record after complaints from the media about excessive secretiveness and poor practice.

Carole Ewart, Convenor of the Campaign for Freedom of Information Scotland and Tommy Kane, an adviser to Labour leader Jeremy Corbyn are also due to take part in a roundtable discussion on the working of the 2002 Freedom of Information (Scotland) Act.

Mr Rumbles said of the advice on SpAds: “This outrageous instruction is designed to cover the tracks of special advisers. There is no other good reason for deleting emails showing how they were involved in the process of responding to FoI requests.

"This instruction is without question unethical and if a request has already been made for this information it is in fact illegal to destroy it.

“The words ‘delete everything else immediately’ are not compatible with good governance, transparency or the SNP's claim to be running the most open government ever.

"Ministers told us last June in Parliament that special advisers were only screening requests for accuracy. This is further evidence their role goes far beyond this and there is significant political involvement in what is supposed to be a non-political and transparent process.

"I expect that this instruction will be of interest to the Information Commissioner."

A Scottish Government spokesperson said: “It is the responsibility of the lead policy official handling the FoI to ensure that documents for the public record, including emails, are correctly stored electronically. It is Scottish Government policy that no private office, including the Special Advisers’ private office, is responsible for retaining email trails.”