Image caption Michael Moore (left) is being replaced in his Scottish secretary role by Alistair Carmichael

Scottish Secretary Michael Moore has been sacked in a reshuffle of the Liberal Democrats' senior team at Westminster.

He is being replaced by the Lib Dems' current chief whip, Alistair Carmichael.

The move comes less than a year before the people of Scotland vote in a referendum on independence.

Mr Moore is thought to be the only cabinet minister on the Lib Dem side of the coalition to lose his job.

It is felt, frankly, that a harder, tougher approach will be needed in the run-up to the September 18 poll than that potentially on offer from Michael Moore.

The party's UK leader Nick Clegg said that someone with a "different experience" was needed in the final year running up to the referendum itself.

BBC Scotland's political editor Brian Taylor blogged that Mr Carmichael has a "secure reputation as a combative Lib Dem chief whip" plus a "dry wit and a cool head".

The MP for Orkney and Shetland was appointed a whip following the coalition agreement in 2010.

In September last year he took over from Jo Swinson as deputy leader of the Scottish Liberal Democrats.

BBC Scotland's Westminster correspondent Tim Reid reported that Mr Moore believed he had done his job "pretty effectively" and that he was "very disappointed" by the move.

Mr Moore tweeted that it had been a great privilege to serve as Scottish secretary and he wished Mr Carmichael "all the best".

After the news broke, Deputy First Minister Nicola Sturgeon tweeted her "best wishes" to Mr Moore.

She added: "A tough opponent but always pleasant. He can take pride in the achievement of the Edinburgh Agreement."

Mr Moore is constituency MP for Berwickshire, Roxburgh and Selkirk and has served at Westminster since 1997.

Media playback is unsupported on your device Media caption Former Scottish Secretary Michael Moore says he is disappointed to be leaving office in Nick Clegg's cabinet reshuffle

He played a key role in the negotiations which led to the Edinburgh Agreement in October last year.

The deal set out terms for a Scottish independence referendum and was signed by Prime Minister David Cameron and First Minister Alex Salmond in Scotland's capital.

Liberal Democrat party leader Nick Clegg has thanked Mr Moore for his work in the post, which he was given three years ago.

In a letter to the MP, Mr Clegg said: "Not only have you successfully piloted through legislation to enable Scotland to take a major step towards the party's long held goal of Home Rule, but you have also ensured that the referendum next year will give the Scottish people a clear and decisive question on which to cast their vote.

"It should be recognised that you secured both the Scotland Act and the Edinburgh Agreement in the context of a majority SNP government at Holyrood, and against a backdrop of an external political narrative that often suggested the legislation would fail and a referendum agreement could not be secured."

He added: "I believe we now need to draw on different experience in the final year running up to the referendum itself and I am keen that just as we have benefited from your formidable skills over the past three years that we take advantage of other experience within our ranks during this period."

Image caption Nick Clegg [right] congratulated Alistair Carmichael outside the Scotland Office in London Image caption There was a series of meetings between Deputy First Minister Nicola Sturgeon and Scottish Secretary Michael Moore ahead of the referendum agreement Image caption Michael Moore was at the top table as the UK and Scottish governments discussed the way forward for the referendum Image caption Michael Moore stood alongside PM David Cameron, First Minister Alex Salmond and Deputy First Minister Nicola Sturgeon on the day the Edinburgh Agreement was signed previous slide next slide

Mr Moore responded by saying it was a "hugely important" time for Scottish politics.

In a letter to Mr Clegg, he said that taking the Scotland Act through parliament and negotiating the Edinburgh Agreement had been highlights of his time in office.

He added: "Over the last few years I have worked with a superb team of civil servants and advisers in the Scotland Office, and other government departments, in very challenging circumstances.

"I do not think the support teams for ministers always get the credit they deserve: I am very grateful for the support they have given me.

"In leaving the Scotland Office I am pleased that Alistair will be succeeding me. As a good friend and long time colleague, I believe he will do a superb job. I wish him all the best."

Following Mr Carmichael's appointment, Labour's Shadow Scottish Secretary, Margaret Curran, said: "I welcome Alistair Carmichael to his new post and pay tribute to Michael Moore. We frequently disagreed, but he has made a significant contribution to the referendum debate and Scottish politics over the past two years."

Meanwhile, in other reshuffle news concerning Scots MPs, Shadow defence secretary Jim Murphy has been moved from that post to the international development brief.

The announcement was made by Labour Party leader Ed Miliband who, along with the Lib Dems and the Tories, have begun reshuffling their top team.