THE leaked memo that inaccurately detailed a conversation between the First Minister and the French Ambassador originated from the UK Government’s Scotland Office.

Secretary of State for Scotland Alistair Carmichael admitted he was ultimately “responsible” for the Scotland Office in confirming the memo had originated within the department. But he dismissed the notion that the memo was a deliberate smear, simply saying that in “the middle of an election campaign, these things happen”.

An inquiry ordered by Sir Jeremy Heywood, the UK’s most senior civil servant, is now under way into the leak of the memo, which First Minister Nicola Sturgeon has described as “categorically, 100 per cent” not true – a claim backed by French officials. The memo was released in the aftermath of the ITV leaders’ debate in which Sturgeon emerged a clear winner. Stewart Hosie, SNP deputy leader, said: “If Mr Carmichael has information about who produced a document containing this false account or indeed about who then leaked it – whether it is from within his own civil service department or elsewhere – then he must provide that information to Sir Jeremy Heywood as a matter of urgency.”

Senior Labour peer Baron Swraj Paul claimed the “dirty tricks” department had been working overtime at Whitehall. Prominent Scottish Labour figures such as Jim Murphy, Kezia Dugdale and Douglas Alexander joined Ed Miliband in attacking the SNP and the First Minister.

But Hosie said: “Labour made a big mistake jumping into this bogus story and are facing a backlash in their own ranks.”

The memo claimed that during a meeting with French officials, Sturgeon said she would “prefer” to see David Cameron remain in Number 10, adding that she did not see Miliband as “Prime Minister material”. Sturgeon denied the claims and received support from the French

Ambassador who said that “absolutely no preference” about the next UK

Prime Minister was expressed during the meeting.

She said: “The real issue is how a second-hand and inaccurate account of this meeting – which was not even attended by the UK Government – came to be written by a UK Government civil servant and then leaked to Tory-supporting newspapers at the start of a General Election campaign.” Writing in The Observer, Sturgeon said the “false account” was “leaked for transparently political motives”.

She said: “I repeat my challenge to Ed Miliband ... will he and Labour join with us in locking David Cameron out of Downing Street?”

Miliband has not ruled out working with the SNP on a vote-by-vote basis but has stopped short of publicly supporting the SNP’s pledge.