The mercury climbed to 16.2C in St James's Park in central London, according to a provisional Met Office reading, easily beating out the previous record of 15.6C set in Cornwall in 1916.

The unprecedented warm start to the year follows the UK seeing its hottest New Year's Eve on record, with several locations in England breaking previous highs set in 2011.

The warmth saw Somerset House in London close its ice rink on Saturday, after officials there said the balmy temperatures impacted the quality of the ice.

"The extremely mild spell is driven by a flow of warm, moist air from the Canary Islands, further south in the Atlantic," the Met Office said.

However, 2022's warm start was set to come to an abrupt end, with daytime temperatures expected to plunge to as low as 3C in the Scottish capital Edinburgh by mid-week, when colder air from the north has moved in.

Meanwhile, 2021 overall was "slightly warmer and slightly drier than average," Mike Kendon of the National Climate Information Centre, said in a summary published by the Met Office.

The year was "likely to fall inside the top 20 warmest years on record for the UK -- a series which begins in 1884," it added, as "our climate is warming".