Financier Malcolm Offord, who last week launched the £400,000 No Borders project, said Labour, the Conservatives and the Liberal Democrats were "at each others' throats" because of the looming General Election.
A former Conservative donor, Offord admits No Borders was partly born out of frustration at pro-UK politicians failing to articulate what ordinary voters feel.
Intended to bring more unheard voices into the referendum campaign, No Borders offers people an online platform, votenoborders.co.uk, to share their "unpolished" feelings about keeping the Union.
Its website carries video testimonials from people who support the UK, who have questions for the Nationalists about independence, and who have ideas about how the Union can evolve.
With Tory sources repeatedly briefing against Better Together's Labour chairman, Alistair Darling, and senior LibDems criticising Labour for not doing enough in the referendum, Offord said he was "worried" about the backbiting within the Better Together campaign.
He said: "They're in an impossible position, because they have three separate political parties. With a Westminster election coming down the line in 12 months, they're going to be at each others' throats.
"How do they then come together and make common policy against Alex Salmond?
"He's very clever the way he's boxed them in. The No Borders campaign is saying to politicians, if you guys can't agree and get your act together that's fine, but we have a point of view on this, and we want to get our voices heard.
"Even if politicians can't articulate what we're thinking, we've got a point of view here."
The 49-year-old said he had never voted for Alex Salmond, but described him as a "clever, brilliant politician" who had run a "very good administration" and outfoxed his opponents.
He said: "I think the lesson of this is the other parties have to get their act together."
A millionaire former fund manager in London, Greenock-born Offord has now started a business investment company called Badenoch & Co in Edinburgh, where he is registered to vote.
He said he had given No Borders £5000 of its £150,000 start-up funding, and had helped raise a lot of the rest through contacts.
However, Offord said other major donors to No Borders would remain anonymous, as the group was deliberately asking for donations below the £7500 legal threshold for naming the source.
"We've said to people we don't want more than £5000. We don't want to be owned by any one person. We don't want to be influenced by any one person. We've said to everybody this is going to be completely anonymous. We're not going to mention anyone's name. There's no need. It's not a big deal."
The group hopes to raise a further £250,000 to help pay for cinema and poster advertising.
Registered as a "permitted participant" with the Electoral Commission, No Borders is only allowed to spend £150,000 in the 16-week regulated period after May 30, meaning it would need to spend all of its other cash before then.
Despite his Tory links - he was also an advisor to the Centre for Social Justice think tank set up by Work and Pensions Secretary Iain Duncan Smith - Offord denied No Borders was a Tory front and said he was not a Tory party member.
After No Borders launched on Thursday it was subjected to torrents of abuse on social media, much of it from supporters of a Yes vote.
A copycat website called votenoborders.com directed people to criticism of No Borders.
Asked if he expected a rough ride personally, Offord said: "What are they going to do to me? I don't have anything to hide. I'm just a local boy from Greenock who got a free education from the state, who went up to London by mistake, and has been trying to come back ever since."
A spokesman for Yes Scotland said: "It comes as no surprise that reports are emerging of serious discord and infighting within the No camp, which is, after all, an uneasy truce between normally warring factions. They have gone steadily from Project Fear to Project Farce."
Asked about Offord's comments, a Better Together spokesman said: "Everybody who believes we are stronger and better together as part of the UK needs to do their bit to win this referendum."