Millions of people are expected to brave sub-zero temperatures tonight to welcome in 2009, in what is forecast to be the coldest New Year’s Eve since the mid-1990s.

The credit crunch will cast a further chill over celebrations, with tickets being offered at discounted prices in many venues yesterday as promoters struggled to fill events. More than a third of Britons will shun bars and clubs and stay at home to save money, a YouGov survey has found.

The Met Office warned those who do venture outside to wrap up well in readiness for a return to the deep freeze of a few weeks ago, during the coldest start to December for more than a decade. Temperatures could drop to minus 6C (21F) in parts of Scotland and minus 4C (25F) in England. “Many parts will be below zero and very frosty. It’s a big contrast to the milder weather we’ve had in the past five years or so,” a Met Office spokesman said.

In London, up to half a million people are expected to gather beside the Thames for one of the world’s biggest parties. Having approved a budget for the event of £1.6 million, Boris Johnson, the Mayor of London, appears to have the same enthusiasm for fireworks as his predecessor, Ken Livingstone.

The programme at the London Eye begins at 8pm and will be broadcast on giant screens in Trafalgar Square and Parliament Square, as well as on BBC One. Prerecorded messages from celebrities will be projected on to the Shell Building on the South Bank.

The mayor is considering scaling back the event from next year, however, amid concerns about crowd safety. Mr Johnson told the London Assembly recently that logistics for the event were challenging because of the huge numbers of people attending. Security and safety measures account for up to 60 per cent of the budget.

A spokesperson for the mayor said that several options were being considered to reduce numbers, including a lottery system for distributing tickets

Manchester will hold the city’s first public New Year’s Eve celebration since the Millennium. The city is also likely to have one of the most boozy celebrations after experiencing the highest alcohol sales in the country over the past few days.

In Birmingham there will be a fireworks display at midnight but in Newcastle upon Tyne the public display will take place much earlier, at 6pm. In Cardiff revellers will be able to sleep off their celebrations in a huge tent that has been set up at the Millennium Stadium.

The cold outlook was good news for Edinburgh, where heavy rain has forced the cancellations of the Hogmanay celebrations in the past. With clear skies and little wind, the conditions were considered almost perfect. At least 100,000 people are expected to cram into the city centre for the street party. Organisers released extra passes yesterday after the first 50,000 sold out four days earlier than last year, despite doubling in cost from £5 to £10. Unclaimed passes reserved for city centre residents and traders were made available after a last-minute rush at the box office.

Last night the torchlight procession that traditionally opens Edinburgh’s new year festivities attracted 20,000 people, a record number.

Tonight’s concert in Princes Street Gardens is headlined by the dance band Groove Armada, who are joined on the bill by Paolo Nutini, who will then hotfoot it west to lead the celebrations in George Square, Glasgow.

Other acts playing Glasgow include the Scots rockers Idlewild, and the Blondie tribute band Bleachie. A crowd of up to 25,000 is expected at the event, which costs £15 and sold out almost a week earlier than last year.

There were fears elsewhere that many people were boycotting New Year’s Eve because of the credit crunch. Some of London’s biggest events, including Koko and the Ministry of Sound, still had tickets available yesterday. Tickets for Elton John’s show at the O2 arena in Greenwich, southeast London, were being offered at a discount. Tickets were also still available for Deacon Blue’s concert at Stirling Castle.

Revellers who do not want the party to finish will be pleased to learn that New Year’s Eve is slightly longer this year — if only by a fraction. British physicists and official timekeepers around the world will insert an extra second or “leap second” into the new year countdown to bring the most accurate atomic clocks in line with the astronomical day.