Image copyright PA Image caption Alistair Carmichael's former special adviser Euan Roddin leaked the memo with his permission

Former Scottish Secretary Alistair Carmichael has rejected calls for him to resign over a leaked memo.

The document, released before the general election, had suggested that Nicola Sturgeon wanted David Cameron to remain as prime minister.

On Friday, a report revealed the Lib Dem MP for Orkney and Shetland had given permission for it to be leaked.

Opponents have urged him to stand down, but he said he wanted to "get on with" working for his constituents.

The confidential memo was written by a civil servant in the Scotland Office and was a third-hand account of a conversation between the Scottish first minister and the French ambassador, in which Ms Sturgeon was reported to have said she wanted David Cameron to remain as prime minister.

Both the first minister and the ambassador insisted this was not the case, and the memo had contained a disclaimer that parts of the conversation may have been "lost in translation".

The official cabinet office inquiry into the leaking of the memo said Mr Carmichael's former special adviser Euan Roddin gave the details to the Daily Telegraph - but he had Mr Carmichael's permission to do so.

The SNP said Mr Carmichael faced a "credibility crisis".

The nationalists have repeated calls for a formal investigation by the Parliamentary Commissioner for Standards into Mr Carmichael's behaviour.

Speaking to BBC Radio Orkney, Mr Carmichael said: "I have said already that I very much regret the position I am in. I have been the member of parliament for Orkney and Shetland for the last 14 years.

"I have worked hard for local people and believe that's the record on which I am entitled to rely and that's the job that I am now going to be getting on with. None of that has changed."

On Saturday, the Scottish Lib Dem's party executive agreed Mr Carmichael would not face any disciplinary action and the party's leader Willie Rennie has said the MP "deserved a second chance".

Image caption Protests have been held in Orkney and Shetland

Ms Sturgeon previously called for Mr Carmichael to consider his position as an MP and described the leak of the confidential memo as a "blatant election dirty trick".

Protests have been held in Kirkwall in Orkney, and Lerwick in Shetland, calling for Mr Carmichael to resign.

Mr Carmichael told BBC Radio Orkney: "We had an account of a discussion, which we believed to be true.

"The first minister and the French ambassador have both said that that was not part of the conversation and we have to accept that as being the truth.

"But the fact of the matter is that the information that came to me, I had no reason to doubt."

SNP MP Pete Wishart said Mr Carmichael must explain if he was sent a copy of the memo.

He said: "Mr Carmichael no longer has any credibility as an MP - the best course of action would be for him to stand down.

"Mr Carmichael must now explain if he was sent a copy of the memo before authorising the leak. If he was, he must then explain why he apparently failed to read his own ministerial papers.

"A formal investigation by the Standards Commissioner would help shed light on these matters."