Chancellor Alistair Darling is expected to announce higher taxes on alcohol and the most polluting cars in his first Budget, due to start at 1230 GMT.
The UK is "better placed than other economies" to weather financial storms, Chancellor Alistair Darling has told MPs in his Budget statement.
Reports suggest he may also replace air passenger duty with a tax on flights.
He is expected to announce higher taxes on alcohol and the most polluting cars but the BBC understands he will delay a planned 2p per litre rise in fuel duty.
But the BBC has learned he will delay a planned 2p rise in fuel duty, after crude oil prices hit a record high.
Reports suggest the chancellor may also replace air passenger duty with a new tax on flights.
The Tories say the government borrowed so much it cannot cut taxes to boost the economy. The Lib Dems say it should prepare the UK for an "economic storm".
But he is unlikely to make big tax cuts due to strained public finances.
EXPECTED ANNOUNCEMENTS Above-inflation rise on alcohol dutiesDelay 2p rise in fuel duty for six monthsReplace air passenger duty with tax on flightsIntroduce 'showroom tax' of up to £2,000 on least fuel efficient vehiclesRequire supermarkets to charge for plastic bags if they do not scrap themMore cash to tackle child povertyHelp with rising energy costs for poorer families href="/1/hi/uk_politics/7291016.stm">Darling to delay fuel duty rise
EXPECTED ANNOUNCEMENTS Above-inflation rise on alcohol dutiesDelay 2p rise in fuel duty for six monthsReplace air passenger duty with tax on flightsIntroduce 'showroom tax' of up to £2,000 on least fuel efficient vehiclesRequire supermarkets to charge for plastic bags if they do not scrap themMore cash to tackle child povertyHelp with rising energy costs for poorer families href="/1/hi/uk_politics/7291841.stm">Key points at-a-glance
Mr Darling is expected to speak in the Commons for up to an hour, with shorter responses from Tory leader David Cameron and Lib Dem leader Nick Clegg.
Other predicted announcements include a requirement for supermarkets to charge for disposable plastic bags, if they do not voluntarily scrap them.
The chancellor is thought unlikely to make big tax cuts, owing to economic uncertainty and strained public finances.
He is likely to delay a 2p increase in petrol duty, which had been due to come into effect on 1 April, due to recent increases in crude oil prices.
Before setting off for the Commons, Mr Darling told the Cabinet his Budget would tackle climate change and help hard-working families while maintaining Britain's economic stability.
But he is expected to announce a "showroom" tax on up to £2,000 on the least fuel efficient vehicles.
He told ministers Britain is well placed to survive global financial turbulence - but stressed the bleak economic background to his statement.
Mr Darling is also expected to announce above-inflation rises on alcohol duties - in an effort to curb binge drinking.
The prime minister's official spokesman said the chancellor received "strong support" from colleagues for the "responsible approach he was taking".
Oil prices
In his Budget statement, Mr Darling is expected to transform air passenger duty into a tax on flights in a bid to cut carbon dioxide emissions, and to introduce a "showroom tax" of up to £2,000 on the least fuel efficient vehicles.
BBC BUDGET COVERAGE There will be a BBC Budget special from 1130 GMT to 1430 GMT with live coverage from the Commons and full reaction and analysis. It can be watched on BBC Two, News 24 and live on the BBC website
But BBC political editor Nick Robinson said soaring crude oil prices, which have gone up by 20% in the past year, were behind the chancellor's decision to postpone the 2p-a-litre rise in fuel duty.
That rise, announced in last year's Budget, was due to come into effect on 1 April, but has been put back six months.
Edmund King, from the AA, said a delay would "help people and business weather the financial damage and uncertainty high prices cause".
But Simon Bullock, from Friends of the Earth, said: "Abandoning plans to increase fuel duty will seriously undermine the government's green credentials."
Alcohol duty
Other predicted announcements include a possible requirement for supermarkets to charge for disposable plastic bags, if they do not voluntarily scrap them.
And Mr Darling is expected to announce above-inflation rises on alcohol duties - in an effort to curb binge drinking.
There may also be more money to tackle child poverty, amid warnings that the government could miss its target of halving child poverty by 2010.
There may also be more money to tackle child poverty, amid warnings that the government could miss its target of halving child poverty by 2010.
And Mr Darling is expected to provide help with rising energy costs for poorer families, which could mean limiting the tariffs paid on pre-paid gas and electricity meters.
And Mr Darling is expected to provide help with rising energy costs for poorer families, which could mean limiting the tariffs paid on pre-paid gas and electricity meters.
He took over as chancellor when Gordon Brown became prime minister last June.
Mr Darling took over as chancellor when Gordon Brown became prime minister last June.
The Conservatives say his hands have been tied by the decisions of his predecessor, who they claim borrowed too much in order to fund public sector reforms.
The Conservatives say Mr Darling's hands have been tied by the decisions of his predecessor, who they claim borrowed too much in order to fund public sector reforms.
Shadow Treasury chief secretary Philip Hammond said: "Alistair Darling's problem is that he is already bumping up against his fiscal rules because they have borrowed so much during that period of relatively strong economic growth.
The Lib Dems say the chancellor should do more to help Britain weather coming economic storms.
Measures to help with high energy costs could be unveiled
"He has got no room for manoeuvre. He can neither significantly increase taxation because of the risks to the economy, nor can he significantly decrease taxation because of the size of the deficit."
The Liberal Democrats' Treasury spokesman, Vince Cable, said some "serious people", including bankers Morgan Stanley, were saying there was a one-in-three chance of a technical recession in the UK this year or next.
"There are very good reasons for believing that there is a high risk of a recession. It is not probable but it is certainly very possible," he said.
"We therefore need to think about how the British economy would cope with it."
He urged Mr Darling to bring house prices within the Bank of England's inflation target and to prepare help for households which would have difficulty paying their mortgages.
Mr Darling is also under pressure from the Confederation of British Industry (CBI) to reduce corporation tax from 28% to 18% by 2016 and to simplify the system.
Trade unions say a cut would lead to tax hikes for "ordinary people".
