JOHANN Lamont has sought to stamp her authority on Scottish Labour as she shores up her power base away from London.

Amid the historic reforms being pushed forward by the party leader, the resignation of general secretary Colin Smyth has been announced. He is due to leave his post after the party conference next month.

The move follows months of infighting over Ms Lamont's bid to shake up her top tier of staff and install her personal choice of operators ahead of the 2014 independence referendum.

The Scottish Labour leader – the first to be in charge of Scottish MPs as well as MSPs – has been seeking to fill key posts with her own appointments since taking over last December.

Her approach followed a full-scale post-mortem of the party's activity, led by Jim Murphy MP, following last year's disastrous election results.

Mr Smyth, 39, said in a statement he will now focus on his role as a councillor in Dumfries, where he lives.

He added: "I was keen to make that move now, before the demands of the rollercoaster of election campaigns start again.

"I fully support Johann in the task of rebuilding the Scottish Labour Party and will serve that cause in any way I am asked to.

"I wish her and all my colleagues well. This may be the end of my time as general secretary but it is not the end of my commitment to the Scottish Labour Party."

Ms Lamont thanked Mr Smyth for his work. She said: "I, on behalf of all the party, thank him for all he has done. I understand his reasons for deciding to move on, but we will miss him in John Smith House."

Mr Smyth was recruited as general secretary – a job held previously by Helen Liddell and Jack McConnell – in 2008 by the then leader Wendy Alexander after working for the party as an organiser.

His future has been the subject of growing speculation as Ms Lamont has sought to implement a restructuring plan drawn up by Mr Murphy, the Shadow Defence Secretary, and Lothian MSP Sarah Boyack last year.

The resignation did not surprise many in the party. One senior figure said: "His departure has been talked of as a possibility or even a likelihood. It's a shame, it was not his fault Labour lost the election."

Mr Smyth's resignation follows the suspension of Scottish Labour's head of communications and policy, Rami Okasha, who faces an inquiry over alleged "insubordination".

It's understood Mr Okasha failed to develop a good working relationship with Paul Sinclair, Ms Lamont's senior adviser.

As the organisational shake-up gathers pace, Ms Lamont is keen to set up a new office in Edinburgh to decide policy and political strategy – with a building near the Scottish Parliament identified as a possible base, sources claim.

The move would leave John Smith House in Glasgow responsible for administrative and membership business.

It is hoped to replace Mr Smyth by Christmas and, in the meantime, the office will be run by Brian Roy – son of Motherwell MP Frank Roy – assisted by Glasgow Provan MSP Paul Martin, a key ally of Ms Lamont's.

Iain McNicol, general secretary of the UK Labour Party, said: "Colin has been a dedicated, loyal and hard-working servant of our party over the past 10 years.

"He has given me great support in my first year as general secretary and delivered a fantastic fight-back in the Scottish local elections this year."

It is understood some Scottish MPs had been initially slow to embrace Ms Lamont's modernisation agenda and delayed changes to organisation and personnel.

Better working relationships are now being forged with Westminster representatives and MSPs.

Ms Lamont's supporters said she was determined to stamp her authority on the party.

But an SNP spokesman said: "Mr Smyth's sudden departure follows reports about Labour factionalism and infighting in Scotland, and the suspension of a senior party official.

"But much of the focus is still on Johann Lamont. After a year in charge, Labour have fallen even further behind the SNP than in their disastrous election showing of 2011.

"If Ms Lamont cannot even lead her own party properly, she can never seriously aspire to lead the country."