In her speech to the party conference in Birmingham tomorrow, Davidson will argue that the Better Together campaign has to achieve an “emphatic” victory to avoid damage to Scotland’s long-term prosperity caused by continuing political uncertainty.
The SNP has said it believes the 2014 referendum is a “once-in-a-generation” event, suggesting that even if there was a “no” vote the matter would be settled for decades.
But Davidson’s warning is designed to address concerns that a narrow victory for the pro-UK cause could bring calls for a speedy re-run of the vote or would act as a catalyst for “devo-max”, under which Scotland would stay in the Union but gain full tax powers.
Senior Tory party figures said yesterday they believed a decisive win in 2014 would demonstrate clear support among Scots for the continuation of the Union and put a limit on new devolutionary powers.
This would create the stable conditions from which the economy would benefit.
In her conference address, Davidson will refer directly to the experience of Quebec, which held referendums in 1980 and 1995, the second after prolonged constitutional rows between opposing parties in a process later called the “Neverendum.”
She will tell English party colleagues at the conference that if victory is to be achieved in 2014, their backing in the campaign would be necessary.
“Victory for the UK in the referendum must be emphatic – it can’t be by an inch, it must be by a mile – to provide the stability essential for our continued prosperity,” she will say.
She will add: “And that is where you can help. We know that during the referendum on separatism in Quebec, it mattered that the rest of Canada said ‘we want you to stay’.”
Davidson’s warning shot comes with Conservatives saying they believe the new Scotland Act reforms – which will hand Holyrood further powers – represent the limit of bilateral transfers from Westminster to Holyrood.
Any further fiscal powers, the Tories argue, would effectively impose a federal system on England, which has so far shown no desire to move that way.
In her speech, she will say: “We cannot get into a situation whereby federalism is forced on England as an answer to any single separatist movement in one of the other nations.”
She points out that with the north east of England having rejected regional assemblies, “nowhere else in England is going to support them”.
Nevertheless, there should be a new body to examine the way the entire UK is run, if Scotland decides to remain within it, Davidson will say.
“We must examine the relationship between the nations of the United Kingdom, all of the United Kingdom, and ensure stability for our lifetimes and beyond.”
The country cannot “continue with a situation where separatists can simply lurch from one opportunity to another to create uncertainty.”
Davidson’s comments follow SNP calls urging David Cameron to spell out exactly what, if any, further powers he supports in the event of a “no” vote in 2014.
The Prime Minister is expected to meet First Minister Alex Salmond next week if negotiations on the shape of the referendum – the number of questions and the extent of the franchise – are ready to be concluded.
Cameron yesterday repeated his claim that it would be a “tragedy” for the UK if Scotland were to back independence and indicated that he would be stepping up his campaign to secure a “no” vote.
He said: “I think we are close [to a deal] and I think we will reach an agreement. I am glad about that, because I think Scotland and the Scottish people deserve a fair, decisive and legal referendum about their future.”
“I dearly hope and will campaign very hard for Scotland to remain part of the United Kingdom rather than opt for separation.
“I think it would a tragedy for Scotland to separate herself from the United Kingdom and I will campaign with everything I have got to say let’s stick together.”
He also said he was prepared to stand alongside opposition politicians to defend the UK.
“I will share a platform with anybody who wants to stand up for the United Kingdom and what it means. I am delighted that Alistair Darling is leading the campaign. He is a man of great integrity. He will do a very good job.”
However, SNP MSP Kenneth Gibson said: “It is becoming clearer by the day that the Tories and other anti-independence parties have nothing to offer Scotland, and Ruth Davidson’s comments suggest they are running scared of the momentum which is building for a ‘yes’ vote to an independent Scotland.
“If the referendum in 2014 is a straight choice between an independent Scotland that protects the benefits of devolution like free university education and free personal care, or a Tory-Labour cuts alliance hell bent on dismantling these policies, the people will say yes to independence.”