Nicola Sturgeon has called on Alistair Carmichael to consider his position as an MP after the former Scottish secretary accepted responsibility for a leaked memo which alleged she wanted David Cameron to win the general election.
Branding the leak as a "dirty trick" aimed at damaging the SNP, Scotland's First Minister said Mr Carmichael should apologise to his constituents "because he clearly contested the election on false pretences".
Mr Carmichael apologised to both Ms Sturgeon and the French ambassador to the UK after a Cabinet Office investigation into the leak concluded he "could and should have stopped the sharing of the memo", and he added that he "accepts responsibility for what occurred".
Ms Sturgeon told BBC News: "Alistair Carmichael has apologised to me and I accept his apology, but I think the people who have got the right to feel pretty aggrieved tonight are the voters in Mr Carmichael's constituency who went to the polls and voted for him on the basis that he had nothing to do with this, because that's what he said during the election campaign.
"It turns out that wasn't true and, not only did he know something about it, he was the person who leaked the document."
She added: "I think he should reflect on his position, he should consider his position.
"I think it is reasonable to say it is at least possible that had voters in his constituency known he had engaged in dirty tricks of this nature during the campaign, then they might have voted differently."
After the leaked memo appeared in a newspaper before the election, Cabinet Secretary Sir Jeremy Heywood ordered an inquiry into how the note, which claimed Ms Sturgeon told French ambassador Sylvie Bermann that she would prefer to see Conservatives remain in power, got into the public domain.
Mr Carmichael, now Scotland's only Lib Dem MP, said that while he had not seen the document before it was published by the Daily Telegraph, he was "aware of its content and agreed that my special adviser (Euan Roddin) should make it public".
He stated: "I should not have agreed this. It was an error of judgment which I regret. I accept full responsibility for the publication of the document...
"Had I still been a government minister, I would have considered this to be a matter that required my resignation. I have therefore informed the Cabinet Secretary that I will decline my ministerial severance payment."
At the time Ms Sturgeon insisted the contents of the memo were ''100% untrue''.
The document was written by a British civil servant following a conversation with consul-general Pierre-Alain Coffinier regarding a meeting between Ms Sturgeon and Ms Bermann.
In his letter to Ms Sturgeon, Mr Carmichael said: "I wish to inform you that I am taking full responsibility for the publication of that document when I was secretary of state... I am clear that this was an error of judgment on my part and wish to offer you my sincere apologies for the embarrassment caused to you and the French ambassador."
The investigation into the source of the leak found an official mobile phone held by Mr Roddin was used to make calls to one of the journalists involved in the story. The special adviser confirmed he had provided a copy of the Scotland Office memo to the journalist, and discussed it with him, believing it was in the public interest to do so.
Mr Carmichael then confirmed that Mr Roddin had asked for his view on the possibility of sharing the document with the press, and that he had agreed this should happen.
A spokesman for Ms Bermann said she would not be making any comment.