Parts of the UK were hotter than California on Monday, ahead of what could be the hottest day of the year so far later this week.

In several locations across the South East, the mercury was recorded at 24.2C (75.56F) in the afternoon, testing the nation’s resolve in maintaining social distancing in parks and open spaces.

The temperature is expected to rise as high as 25C (77F) on Tuesday and 27C (80.6F) on Wednesday, which would surpass the 26.6C (79.88F) recorded in Treknow, Cornwall, on Good Friday.

The UK was warmer on Monday than some leading tourist hotspots including Ibiza and Malibu.

The temperature in Scotland and Northern Ireland rose to highs of 18C (64.4F), while Wales hit 18.8C (65.84F), and northern England reached 22C (71.6F) by mid-afternoon.

Early-morning swimmers entered the water at Britain’s oldest swimming club at the Serpentine in Hyde Park, west London, on Monday morning, after the easing of coronavirus lockdown measures.

The boss of London’s Olympic Park, Mark Camley, said the capital’s open spaces are likely to see “increasing numbers of people” as the weather remains warm and dry.

There will be a “north-south divide” on Tuesday morning, according to Met Office forecaster Alex Burkill, as parts in Scotland will see light rain and drizzle.

But by the afternoon it will be warm and bright for large swathes of the UK.

Mr Burkill said: “It will be very bright for most in the UK, with warm temperatures and clear, blue skies. By the afternoon, parts in London and the South East could see highs of 25C (77F), while most other areas in the UK should hit the low 20s.

“But Wednesday could be the hottest day of the year so far, with the temperature potentially reaching a high of 27C (80.6F).

“Large swathes of the UK will be dry and sunny for all, as warm air moves in from the south.”