Warnings have been issued over social distancing and possible police intervention after thousands of people in south London have made the most of the warmest day in March for over 50 years.

Health Secretary Matt Hancock tweeted out a warning telling people not to "blow it" in the sunny weather this week, and with Easter approaching.

Police forces have warned people across the UK that they large crowds gathering in parks will be broken up.

The "exceptionally warm" spell of weather has seen large numbers flock to London parks and green spaces for the three-day mini heatwave starting on Monday and stretching to today (March 31).

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In St James's Park, London, temperatures yesterday reached 24.2C, the hottest recorded in March since 1968, and across south London peaked above 23C.

Images of groups gathering in the sunshine in sunshine, as well as extreme cases in Birmingham, Leeds and Nottingham where police had to shut two parks, led to Prof Sian Griffiths to issue a warning about obeying the rules.

Leeds. QingD/PA Wire

Leeds. QingD/PA Wire

The senior public health official told the BBC: “If we want to control the spread of the virus, it’s much better to be seeing people outside… but we also need to be keeping our distance from each other.”

"When I see the pictures I do get anxious," says Prof Griffiths, who co-chaired the Hong Kong government's inquiry into the SARS outbreak in 2003.

"If we're not in a household bubble we need to be two metres apart and I don't think those pictures look like that's happening."

Politicians have warned people to remain "cautious" while visiting parks and beaches after large crowds were seen gathering in public spaces in warm weather on Tuesday.

Communities Secretary Robert Jenrick urged people to enjoy the sunshine in a "sensible, cautious" manner by sticking to the rules.

Leeds. Sophie Meredith/PA Wire

Leeds. Sophie Meredith/PA Wire

He told ITV's Good Morning Britain: "We just need to exercise caution and be sensible and pragmatic about how we do that.

"I think the vast majority of people are and will do that, they will enjoy the sunshine this week and at the Easter weekend, but they'll do so in a sensible, cautious way.

"The two things aren't mutually exclusive - you can go and out, have fun, enjoy the great outdoors and the sunshine, while also trying to be careful, sticking to the rules and trying to avoid the most crowded places."

Temperatures will drop to the low teens in the east of England from Thursday.

The Met Office said a "cold front" will start moving down from the north, bringing with it colder, windier conditions in stark contrast to the previous "warm southerly winds".

Wet weather is forecast for Easter Sunday, with the chance of sleet or snow in Scotland and the far north of England.

Mr Madge added: "Friday should mark a rather malign start to Easter, with colder conditions for large swathes of the country as part of an Arctic plunge.

"Temperatures will be dragged down quite a bit from the day before, with wintry showers expected in Scotland and the most northern regions in England."