Last year, the Tories broke convention and voted against the whole package instead of proposing amendments.

If they do so again tonight, Lib Dems are likely to vote against it as well.

The potential embarrassment for ministers comes after they were taunted in the Commons again over the Queen's speech on the final day of debate.

Conservatives seized on moves towards European harmonisation of taxes to accuse the government of "fiddling while Britain's economy slides down".

The government is "fiddling" says Francis Maude

Shadow Chancellor Francis Maude said: "There is a clear commitment in Labour policy documents to taking further a process of tax co-ordination and harmonisation which can only have the effect of increasing Britain's taxes to Continental levels."

Chancellor Gordon Brown has dismissed as "scare stories" suggestions that Britain was to be forced to bring VAT and other taxes into line with the rest of Europe.

On the wider economy, Mr Maude said the government had squandered opportunities to make genuine improvements to health and education services.

Ministers had missed the chance to "mitigate the effects of an economic downturn ... triggered by the government's own blunders," he said.

Barely a day went by without further job losses announced, Mr Maude said. But, incredibly, he went on, there was not one line in the Queen's speech that would make it easier for a single person to get a job.

But Treasury Chief Secretary Stephen Byers condemned "scaremongering" on EU tax harmonisation.

"This government has made it clear that we will not support any action at European level that will threaten jobs or the competitive position of British business," he said.

"So any tax proposals will need to pass that acid test. Questions of tax require a decision, so there is no question of tax changes that we do not support being imposed on us by Brussels."

Speech amendments

Last week, Lib Dems leader Paddy Ashdown branded the Queen's speech legislative programme a timid package of measures.

Paddy Ashdown faces internal criticism

But his MPs reportedly went against his wishes in deciding to vote against it.

They will propose their own amendment, setting out what they would have liked to have seen.

Sources said that having tabled a critical amendment, joining the Tories in an outright vote - if there is one - against the whole package is the only consistent thing to do.

The Tories are expected to propose their own amendment, which has no hope of being passed, and then to force a vote on the government's motion backing the speech itself.

Lib Dem MPs are unhappy at omissions, such as a freedom of information bill and preparations for joining a single currency.

Mr Ashdown has faced internal criticism since announcing closer co-operation with the government two weeks ago.