SIR Peter Housden, Scotland's top civil servant, was last night called upon to resign over the growing row involving allegations he had "gone native" and become too close to the SNP Government and its cause of Scottish independence.

The demand from Labour peer Lord Foulkes came after the matter was raised in the House of Lords. Several peers vented their fury at Sir Peter and accused him of abandoning the important, traditional role of civil service impartiality.

All three opposition leaders at Holyrood have written to the head of the civil service, Sir Gus O’Donnell, the Cabinet Secretary. They have expressed concern at what they see as the politicisation of the civil service in Scotland.

This followed the leaking of an internal memo to staff from Sir Peter, the £185,000-a-year Permanent Secretary, in which he said the constitutional question had moved on from the Coalition’s plans to devolve more power to the Scottish Parliament.

He wrote: “It is remarkable how the terms of this debate have changed irrevocably in just three weeks. Calman and the status quo now seem lost in the mists of time.”

In one passage, he urged staff to see a play called Dunsinane, a tale about an English army seeking to impose order on Scotland.

Last night, Lord Foulkes told The Herald: “I don’t think Sir Peter can continue given he does not have the confidence of the political leaders in Scotland.”

Asked if he was calling for the Permanent Secretary to resign, the Labour peer said: “Absolutely. He has crossed the line for political impartiality and got involved in party politics.”

Earlier, Lord Foulkes raised the issue at Westminster, accusing Sir Peter of advising Alex Salmond and his colleagues on the “tactics and policy in relation to the break-up of the UK”.

Lord Forsyth, the Conservative peer, said: “What is going on when the Permanent Secretary of the Scottish Executive is circulating what is described as an internal blog to civil servants in the Scotland Office which, among other things, advises them to go and see a play about an army of occupation in 11th century Scotland, which he said ‘does genuinely speak to our present condition as a nation’.”

Lord Stephen, the Liberal Democrat peer and former deputy first minister, said: “Most people in Scotland would far rather highly paid civil servants spent their time improving the education system, the health service and the transport networks in Scotland rather than pandering to the party political objectives of our First Minister in Scotland.”

Labour’s Lord McFall said Sir Peter had “crossed a line” while former Conservative whip, Lord Douglas of Selkirk, suggested civil servants should be “above suspicion”.

However, Lord Butler, a former Cabinet secretary, noted that, just as it was the duty of civil servants elsewhere to support the policies of the Government they serve, “so it is the duty of the civil service in Scotland to advise on the policies of the Scottish Executive”.

Lord Wallace of Saltaire for the Coalition agreed it was important the civil service working for the Scottish Government “command the confidence of the Scottish ministers of the day regardless of their political complexion”.

Earlier, he quoted from the civil service code, highlighting how civil servants must be impartial and “serve equally well governments of different political persuasions”.

Without going into detail, Lord Wallace later added: “Discussions are underway to ensure that civil servants remain impartial.”

Sir Gus’s response to opposition leaders Iain Gray, Annabel Goldie and Willie Rennie is expected to be published in the next week or so.