A school in Reading will allow students to wear their PE kit to class on the hottest day of the year.

Experts predict the hot spell in Reading is set to build to a crescendo on Friday as temperatures are expected to soar to a sizzling 31C in the town, and 34C in some parts of south-east England.

The UK Health Security Agency (UKHSA) issued an amber heat-health alert on Thursday, warning residents to look out for young children, babies and older people.

Writing on Facebook, a representative of Highdown School and Sixth Form Centre said: “Tomorrow is going to be a hot day and, as a result, we want students to feel comfortable during The Great Get Together.

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“Therefore students can decide if they would like to wear their uniform as normal or their Highdown PE kit.

“Their attire cannot be a mix of items and must be the correct Highdown uniform. 

“Please remember to encourage students to bring a hat, sun cream and water. There is a lot of shade which we will encourage students to use.”

The warm flow of weather is coming from Spain and Portugal, where daytime temperatures have exceeded 40C in southern Spain.

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Britain’s highest recorded June UK temperature was 35.6C at Southampton Mayflower Park in June 1976 – the year of a notorious summer heatwave.

Before Wednesday, this year’s hottest day so far was the 27.5C set in mid-May at Heathrow.

Dr Mark McCarthy, head of the Met Office’s National Climate Information Centre, said: “Climate change has increased the average temperature of UK summers, and it is also increasing the likelihood of experiencing more extreme temperatures during hot spells and heatwaves.

“Reaching 34C during June is a rare, but not unprecedented, event in the historical climate records for the UK. But if it should happen this week it would be notable that it would have occurred on three days during the last six Junes.”