Allan Grogan, a party member in Angus, said he became disillusioned with the attitude within Labour that it should automatically be pro-Union and decided to test his belief that there were others within the party who shared his views.
He created Labour for Independence, and established a website and a presence on Facebook which has gone from just 13 indications of approval a few weeks ago to 334 at the weekend, overtaking the main Scottish Labour score.
More importantly, 24,000 people have looked at the Facebook entry and in just a week the website has had 2000 hits. While many are SNP members or voters sending messages of encouragement, significant numbers claim to be Labour Party members sharing his view.
Now Blair Jenkins, chief executive of Yes Scotland, has welcomed the group into the ranks of those backing independence and has himself been interviewed by Mr Grogan for his website.
This comes as Yes Scotland demonstrates the extent of its ambition by advertising for four senior executives to work under Mr Jenkins at a new headquarters to be established in Glasgow.
These four directors – of operations, communications, marketing and communities – will all have staff of their own.
Mr Jenkins said: "When I accepted the position of chief executive of Yes Scotland, I made it clear that I wanted the campaign to provide the kind of high-quality information that the people of Scotland will need in order to make the right choice.
"To be able to do that, I am determined to build a strong team and organisation and I am confident that the people who fill the four senior positions being advertised will be of the highest calibre and expertise."
Mr Grogan was a Labour sympathiser for as long as he could remember and a party member in his late teens and early 20s before going to work as an English teacher in the Far East. After his return to Scotland he rejoined the party two years ago and worked for it in election campaigns.
When he argued in favour of independence he was told he should go off and vote for the SNP, prompting him to try to start a debate within the party.
He said he was unsure if he was completely out of step, coming from Angus, which is not a Labour heartland, but the response from many members in Glasgow and Ayrshire has convinced him there is a genuine appetite for a change of direction. Mr Grogan, who has been invited to address a pro-independence rally in Edinburgh in September, says on the website: "There are many in the Labour party who seek and support an independent Scotland.
"There are also many supporters who once were Labour but have lost faith or moved political ideology because of a Labour party more concerned with middle England than their core bases, especially Scotland."
Labour MSP Richard Baker said: "Labour members have the right to bring policy suggestions to conference where they can be debated. However, as we are focused on social justice in the widest sense, we believe that we all achieve more together than apart.
"I also note that the website has lots of support from SNP backers, but lacks any real support from within our own ranks. Scottish Labour will fight to keep Britain together because we believe that we are stronger together."
But Mr Jenkins said: "We know there are many voters, of all political persuasions and none, who support an independent Scotland. In fact, the principle of independence for Scotland is above and beyond any party political interests.
"It's the people's referendum. Whether people support Labour, the Conservatives, the SNP, the Greens or any other party, there are many who are attracted by the possibilities that independence offers to build and shape the kind of society that is in line with their core beliefs and values."
He added: "Another major plus side of independence is the prospect of the best of the talent from the various parties serving at Holyrood rather than Westminster."