Hundreds of thousands of New Year revellers have welcomed in 2011 with a bang, packing the streets to watch spectacular firework displays light up the skies of London and Edinburgh.
An estimated 250,000 party-goers congregated around The London Eye for the capital's pyrotechnics extravaganza, while around 80,000 people attended the annual Hogmanay party in Edinburgh.
And the celebrations are set to continue with half a million people expecting to flock to Westminster for the 25th New Year's Day parade.
The Metropolitan Police, who had 3,000 officers on duty, said 77 arrests were made during London's New Year celebrations. The majority (24) were for public order offences, while 16 revellers were arrested for assault and five for sexual offences.
Crowds gathered along the banks of the River Thames and spilled into Trafalgar Square, before a music-accompanied fireworks display illuminated the sky on the stroke of midnight.
The heavy cloud cover failed to hinder the spectacular 10 minute display, that saw showers of brightly coloured fireworks shoot from the London Eye to a soundtrack including Queen's We Will Rock You, The Beatles Lucy in the Sky with Diamonds, and Blur's Song 2.
In Edinburgh, partygoers enjoyed the world-famous Hogmanay street party and festival, which began on Thursday with a torchlight procession along the Royal Mile.
Fireworks lit up lit up the sky above Edinburgh Castle at midnight, before revellers joined in a mass rendition of Auld Lang Syne.
Earlier in the evening, Scots rockers Biffy Clyro performed to a capacity crowd at the Concert in the Gardens.
In London, more than 10,000 musicians, cheerleaders and performers, including those from 20 London boroughs and 20 countries, will take part in the free 2.2 mile New Year's Day parade. A special message from the Queen will be read out to start proceedings.