Labour and Conservative politicians are to join forces next week to launch the anti-independence Better Together campaign.
Labour finance spokesman Richard Baker, who is director of Better Together, said: "The SNP threw down the gauntlet. We've picked it up".
Mr Baker holds a joint directorship in Better Together 2012 Ltd, the company set up to manage the campaign, along with former chancellor Alistair Darling and Scottish Conservative constitutional spokesman David McLetchie.
Supporters of independence organised a series of 45 community events over the weekend, claiming the Yes Scotland campaign was "about people and not politicians".
A Yes Scotland spokeswoman said: "We are the fastest-growing campaign in Scotland and set to be the biggest. In contrast, the No campaign are looking to organise a couple of leafleting sessions on Monday morning."
Mr Baker called for the independence referendum to focus on a single question rather than "muddy the waters" with a "devo max" or "devo plus" alternative.
He said: "The reason Alex Salmond now wants two questions is because his is scared of one question.
"Alex Salmond, the leader of the SNP, must be the first politician to campaign all his life for a clear-cut vote on independence only to run for cover when he is offered the chance."
The Better Together campaign will be hatched in Napier University's egg-shaped lecture theatre in Craiglockhart, Edinburgh on Monday.
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