In pictures: Britain basks in hottest day of the year so far

Britons have been basking in the sunshine as temperatures soared over 30C on Friday, as forecasters predict it could be the hottest June on record.

The Met Office said temperatures reached 30.7C (82F) at Heathrow just after midday on Friday and could climb still further to 34C (93F) for parts of the South East, where the Met Office predicts there could be “the hottest Royal Ascot on record” in Berkshire.

For the first time ever, men were allowed to remove their ties at the prestigious racing event as organisers sought to keep people as comfortable as possible.

A spokesperson for Royal Ascot said "common sense" had to be applied in regards to the temperatures and added: "The dress code has been relaxed – this means that racegoers will be expected to arrive compliant but can remove jackets and ties as the day goes on due to the high temperatures."

The temperature record for the year was broken for the third consecutive day, with the previous high of 29.5C (85.1F) recorded at Northolt in west London on Thursday, which surpassed the high of 28.2C (82.76F) recorded at Kew Gardens on Wednesday.

The UK Health Security Agency has issued a Level 3 heat-health alert for London, the East of England and the South East in order to protect health services.

Agostinho Sousa of the UKHSA told BBC Breakfast that the alert “is to inform our partners that they should prepare their services for possible increases in demand due to increases in temperatures."

Network Rail warned services may experience delays and disruption on Friday because of the heat, which can cause overhead wires to sag and the steel rails to buckle, and advises citizens to check before they travel.

“We can’t change the weather, but it can change your plans,” the organisation said on its website.