Alex Salmond has been criticised for pressing ahead with a doomed independence referendum bill at an estimated cost of more than £2.5m to taxpayers.

The first minister is determined to introduce the legislation to the Scottish parliament in the new year, despite knowing it will fail. The three main opposition parties have said they will vote it down.

To date, more than £1m has been spent on the national conversation, which was introduced two years ago to give the public a say in Scotland’s constitutional future.

Ministers are proposing to spend another £434,000 on St Andrew’s Day celebrations later this month, when the referendum white paper will be launched, and a further £640,000 on civil servants’ pay by giving them a public holiday. In addition, at least £500,000 is expected to be spent drafting the legislation.

The bill was sunk last week-end when Liberal Democrat MSPs agreed they would not support it. The Lib Dem leadership has not ruled out backing a referendum after the next Scottish election in 2011 but it believes ministers should put the constitutional issue to one side until after the recession.

Iain Gray, leader of the Scottish Labour group at Holyrood, said Salmond should ditch the bill now to avoid wasting any more public money. The £2.5m cost would pay the salaries of 100 teachers, nurses and policemen for a year.

“The national conversation has already been exposed as nothing more than a long-running SNP rally at the taxpayers’ expense,” he said. “To increase spending on it shows how out of touch the nationalists are with the country.

“Alex Salmond should be concentrating on economic recovery for all of Scotland not in this self-indulgent monologue.”

Annabel Goldie, leader of the Scottish Conservatives, said that if the bill succeeded and a referendum were held, it would bring the total cost of the exercise to around £9m.

“The cat is out the bag. In the middle of Labour’s recession, where belts will have to be tightened, the SNP wants to spend £9m of taxpayers’ money on Alex Salmond’s rigged referendum,” she said.

A source close to Tavish Scott, leader of the Scottish Lib Dems, said: “We are opposed to a referendum now but Tavish has an open mind about a referendum after 2011. Ross Finnie will continue to take soundings from the party over the next two years on this issue.”

While ministers are privately resigned to losing a vote on the bill, they are determined to press ahead, giving the SNP the option at the next election of claiming that opposition parties denied voters a say in the country’s constitutional future.

They also want to use the apparatus of the civil service to generate as much publicity for the issue as possible, aware that this may build up support for a referendum in the future.

Michael Russell, the minister in charge of the referendum, insisted the plans were value for money. He added: “The national conversation is all about empowering the people of Scotland to have a say on their future in a free and fair vote — reflecting the overwhelming majority of voters across all the parties who support a referendum.

“It is about Scotland acquiring the responsibilities so that we are not faced with a £100 billion bill for a new generation of weapons of mass destruction, or £5 billion for unnecessary ID cards, or getting dragged into illegal wars such as Iraq at the cost of billions more pounds.”

This weekend, Russell heavily criticised the Calman commission, set up by opposition parties to investigate more powers for the Scottish parliament.

The commission, which reported in the summer, recommended a new Scottish income tax.

Ahead of a lecture he will deliver on Scotland’s constitutional future at University College London tomorrow, Russell derided the commission as a “missed opportunity” and warned opposition parties not to stand in the way of holding a referendum.

“The success of the parliament has inevitably led to a hunger for further reform of the devolution settlement,” he said. “The establishment of the Calman commission recognised that hunger — but it provided very limited nourishment. Let me be clear: there are recommendations within their report — around half of the total — that we agree with.

“But the commission was strictly limited in its remit and its outcomes. On several key issues, most notably finance, Calman’s recommendations are either flawed or do not go nearly far enough. Scotland would remain reliant on UK government funding, and what the Treasury gave with one hand it could take away with the other.

“I firmly believe that Scotland will not fulfil its potential until the powers of the parliament are complete and Scotland is independent.

“Our national conversation, unlike the Calman commission, is prepared to welcome all views. The Scottish government, unlike the UK government, believes that the Scottish public should have their voice heard on Scotland’s constitutional future.”

The Conservatives yesterday denied claims by the Scottish government that David Cameron was a “hypocrite” for refusing to back a poll on independence while supporting a vote on greater powers for the Welsh assembly.

A Tory spokesman said they would not stand in the way of a referendum if it was passed by the Scottish parliament. “But there is no majority for a referendum — it is not on the agenda,” he said.

Times Recommends

• How I lost the gift of joy for a while
• Why Ann Widdecombe has got it wrong
• Alas, it’s the end of the road for petrolheads