An estimated 350,000 people crowded central London and the banks of the Thames to watch the annual firework display over the London Eye.
In Scotland, meanwhile, the world renowned Hogmanay street party in Edinburgh attracted an estimated 50,000 revellers from across the UK and as far afield as South Africa and New Zealand.
Calennig celebrations at Cardiff Castle in Wales drew 30,000-strong crowds, while an open air concert in Belfast helped 5,500 to party in the New Year.
London Mayor Ken Livingston was quoted by the BBC as saying: "London's New Year's Eve fireworks display is world famous and the capital one of the best places in the world to be during the festive season.
"Its success is down to the many organisations, including police, transport and local authorities, that come together to provide a stunning backdrop to the capital's celebrations."
