If David Cameron wanted a strong reaction in Scotland, he succeeded. Barely 24 hours after he had revealed plans to help set up the referendum on Scottish independence, callers to BBC Radio Scotland's phone-in show on Monday morning shouted about "perfidious Albion", others warned of an "anti-English" backlash and one urged the prime minister to "butt out" of Scotland's affairs.

The prime minister's offer provoked exactly the response that Alex Salmond, the first minister, craves and many of the government's supporters feared. His proposals that Westminster could legislate for the referendum led to immediate claims that an Eton-educated Tory, whose party has just one MP in Scotland, appeared to be dictating terms to the Scottish people.

"Mary in Edinburgh", one of the first callers on air during Monday's Call Kaye phone-in show, stressed "I'm not for independence at all" but added: "I worry that an intervention from Westminster may result in an anti-English kneejerk vote".

She echoed the main anxiety of many non-nationalist politicians, particularly the Labour and Liberal Democrat MSPs and MPs struggling to combat the rampant nationalists: that the Tories and the UK coalition government may be so toxic to Scottish voters that any intervention would drive up support for separation.

Another caller made this view clear, articulating one of the most powerful historic grievances amongst nationalists: that Scotland was a subject state. "We're dealing with perfidious Albion here. If anyone seriously thinks that the British empire is really going to deal fairly with a small nation in any way, forget it."

"Jim from Dundee", the caller who urged Cameron to "butt out of it all altogether", insisted he was not a Scottish National party member but said the SNP was being faithful to its promise at May's election, when Salmond won a historic landslide. The nationalists made a "basic, fundamental promise" to hold the referendum on their own terms, Jim said.

By the time Call Kaye went on air, Nicola Sturgeon, the deputy first minister of Scotland, had made that the main nationalist theme. She said Cameron's gambit was a blatant attempt to meddle in internal Scottish affairs. "It's the attachment of conditions that gives the game away – this is Westminster trying to interfere," she said on BBC Radio 4's Today programme.

"Perhaps I should be relaxed about that because the more a Tory government tries to interfere in Scottish democracy then I suspect the greater the support for independence will be, but there is a key issue of democratic principle here."

Salmond's chief spokesman accused the UK government of contortions, and of dragging itself into a political quagmire by intervening on a policy it had never supported. "The only democratic mandate to hold a referendum on Scotland's independence is with the SNP," he said.

This backlash, echoed and amplified by nationalists on Twitter and Facebook, was not what Cameron's advisers had prepared for when, on the Andrew Marr Show on Sunday, the prime minister revealed his gamble to take the independence referendum head-on by helping it happen.

The prime minister's line was simple: the continued delay and obfuscation by Salmond about the timing, nature and legality of the referendum was damaging Scotland and its economy. He insisted the vote should be "fair, legal and decisive".

His government's legal advice was clear and unambiguous: under the Scotland Act setting up Holyrood in 1999, the Scottish government was explicitly barred from passing any legislation which affected the constitution of the UK. So, despite opposing independence, the UK government would bring forward legislation to make the referendum legal; Cameron implied this was a noble, generous act. "We're not going to dictate this, this is something we want to resolve, the legal position," he said.

It should have been a masterstroke. It would be the first time the pro-UK parties had effectively challenged Salmond on his main battleground: the constitutional future of Scotland and the UK. Facing opposition parties humiliated and despondent after their comprehensive defeat in May, the first minister dominated the political landscape in 2011. After several months of careful planning, Downing Street hoped Cameron's intervention, on the Sunday before both the Westminster and Holyrood parliaments resume after the Christmas recess, would give the UK government first blood in 2012, allowing the Westminster parties to control the constitutional agenda at last.

But there was immediate confusion about what Cameron meant. In Scotland, papers ran differing interpretations of the No 10 strategy after being briefed by different ministerial and official sources.

One paper said Cameron would ban Salmond from staging the referendum unless he gave in to a list of UK government demands; several reported there would be an 18-month deadline for the new legal power to be used; some referred to a "sunset clause" built into the new power; another said Salmond would be told to hold the poll by August 2013, while others said Salmond would be barred from using the official electoral roll for the referendum if he refused Cameron's offer. One report suggested the UK government would also ask Scottish voters how the referendum should be worded.

After Sturgeon's comments, UK government sources admitted they had lost the initiative. Senior Lib Dems within the coalition and their erstwhile Labour supporters were furious.

In a determined effort to wrest back control, the official statement on the referendum will now be rushed into Westminster several days earlier than planned. It is now expected to be published in the Commons on Tuesday, the first day after the Christmas recess, by Michael Moore, the secretary of state for Scotland.

Whitehall sources tried to play down the lines spun by SNP sources on Sunday: there would be no sunset clause; no explicit time limit; no talk of banning Salmond from staging the referendum; no demand that it be run by the UK Electoral Commission, a proposal repeatedly ruled out by Salmond.

What is clear is that UK ministers will promise to make the referendum legal, using a so-called Section 30 order under the Scotland Act, if Salmond asks just one question and does not put forward the extra options he has floated, of greater powers for Holyrood short of independence. They also want the referendum staged in 2013, the only year between now and 2016 without a major election.

Clearly spooked by the nationalist attacks and internal disputes about the mishandling of the briefings, Whitehall officials insist their proposal is to facilitate a referendum run solely in Scotland, not one dictated by Westminster.

Moore will stress his Scottish credentials when he takes the Commons dispatch box. In a statement on Monday designed to quell that clamour, Moore said: "As a Scot I think it is vital that the Scottish people can make a clear decision about our future within the United Kingdom … Our priority is to ensure that the decision is taken in Scotland, by people in Scotland."

Despite the confusion on Sunday, UK ministers hope Moore's statement will kill off the confusion and focus attention on their core objectives: to present Salmond with a dilemma and to allow Scottish voters to draw the conclusion that Salmond's government is being evasive and self-serving by refusing to give a clear date, question or structure for the referendum.

There is an implied threat at the heart of this offer: if Salmond refuses it, then he faces legal challenges from pro-UK lawyers and pressure groups which will prevent the referendum being held for several years. Any judge in that case will look critically at the Scottish government for rejecting Cameron's offer to make the referendum legally watertight.

The timing of this intervention is crucial for a second reason: Salmond faces an offer of further concessions from the UK government. Later this month, Holyrood will be asked to vote on whether it accepts new tax-raising and borrowing powers under the Scotland bill currently going through the House of Lords. If it rejects them, UK ministers will again accuse Salmond of putting personal grievance and ambition before Scotland's interests.

Will Rennie, the Scottish Lib Dem leader, said he believed Salmond will eventually accept the Cameron offer. "If he rejects the offer, this would end up in the courts for years. In my most cynical periods I suspect Salmond wants this, as his plan B. If he doesn't win the referendum, he can develop grudge and grievance as this drags on through the courts," he said. "But the SNP hasn't said no today. I think they might accept this in the end. Ultimately they will want this power."