This year’s Royal Ascot could come close to the hottest on record, forecasters have said, as sweltering temperatures hit the UK.

It had already reached 28C (82F) in Heathrow before midday on Friday, and could reach 34C (93F) in the afternoon for parts of the South East, near to where the annual horse racing meet takes place in Berkshire.

As the mercury soared, heat-health alerts were issued for parts of England, and Network Rail warned services could be disrupted by the warm weather.

Stephen Dixon, spokesman for the Met Office, said: “One thing we are keeping an eye on is Royal Ascot.

“The highest maximum temperature we’ve had on a day is 32.8 degrees, which is taken from a nearby station in Reading near Royal Ascot.”

This temperature was recorded on June 21 2017.

He added: “It’s looking like it could be around 31 degrees in Reading today, but I wouldn’t rule out the possibility of it perhaps rising into 32, and then obviously getting closer to that record, but it’s something that might be quite close to being the hottest Royal Ascot on record.”

Predicted high temperatures have meant men in all enclosures at Ascot were allowed to remove their jackets and ties once the traditional royal carriage procession had ended.

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.

“We also have a Level 2 that is currently active in the South West and East of England that is to inform our partners that they should prepare their services in case they need to enter into action in case we see an increase in temperatures.

“Right now the situation is stable, and we expect the temperatures to drop tomorrow.”

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.

Sunworshippers may not have long left to enjoy the balmy weather.

Mr Dixon said the heatwave is due to end shortly, as a cold front coming in from the North will bring with it “a drop in temperatures” and “a spell of some rain through the day on Saturday for much of central England and Wales.”

But those still hoping to chase the sun as the heatwave comes to an end can expect hot temperatures to remain on the south coast.

“The far south coast of England will hold on to the highest temperatures the longest, possibly up to 31 degrees across some of that far southern coast of England tomorrow,” Mr Dixon added.

The highest recorded June temperature in the UK was 35.6C (95F) at Southampton Mayflower Park in June 1976, and forecasters do not expect the record to be surpassed this week.