People have been enjoying the sun, with some roads busy and train services packed as crowds head to the coast.
Temperatures have so far peaked at 25.5C in Northolt in London and 25.2C in Herstmonceux, east Sussex.
Wales saw a high of 23C in Usk, Monmouthshire while in Scotland the mercury rose to 21.7C in Charterhall.
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Cyclists pass Belvoir Castle, Leicestershire ahead of an early May Bank Holiday Monday which could break temperature records
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The scene at Fisherrow Harbour in Musselburgh, East Lothian, was a serene picture of blue
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So many people decided to head to Brighton and other South Coast seaside destinations that Southern Rail "strongly advised" passengers not to travel. Engineering work had seen trains replaced by replacement bus services
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Four retired firefighters, members of a group set up to preserve a former London Fire Brigade engine, enjoy the Brighton seafront after travelling from London
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The sun shines brightly in a garden in Manchester, where temperatures rose to 23C
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Not a cloud in the sky above Chichester in West Sussex, where temperatures are expected to stay at a pleasant 23C on Monday
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And also in Chichester, Itchenor Sailing Club shared this photo of the harbour where they are hosting an open day
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The sea was glistening off the coast of Paignton in Devon, photographed by a runner
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Meanwhile in Poole, Dorset, this exotic sunset scene looks like it is straight out of a holiday brochure
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Many walkers made the most of the clear skies and took to the hills in the Brecon Beacons
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Sunday in London began with a glorious red sunrise, pictured here over the city from Richmond Park. The temperature in the capital reached 24C