Official: It's the hottest July day ever

It breaks the previous July maximum temperature of 36C recorded at Epsom, in Surrey, in 1911, the Met Office said.

It was an uncomfortable night for Londoners, with temperatures dipping to just 21C at 2am and a low of 19C by 6am.

But the Met said it was unlikely that the all time high temperature record of 38.5C - set in Faversham, Kent, on August 10, 2003 - would be passed.

Schools close early

Two London schools have suspended their sports days, while several others will close at 1.30pm, two hours early, Westminster Council said.

The move is part of a raft of measures being taken to prevent people falling ill during the hot weather.

Yesterday was the hottest day of the year so far, with temperatures reaching 33.2C at Heathrow Airport.

Today temperatures are expected to peak west of London in the late afternoon.

Hospitals across the country are on high alert to prevent any repetition of the 2003 heatwave across Europe which claimed 27,000 lives.

Deaths of over-75s in London increased by more than 60 per cent that summer.

Elderly warned

The London Government Association yesterday issued "practical steps to stop older people dying in the heatwave".

LGA Community and Wellbeing Board chairman David Rogers said: "People die because heat puts a greater strain on their hearts to pump blood. When older people die during a heat wave, they usually are not exercising, they are typically sitting in a very hot room."

Westminster Councilor Ian Adams said: "Heatwaves like the one we are experiencing now can cause a lot of unnecessary illness, especially among old people, who are particularly vulnerable.

"Older people are less able to feel the heat and don't sweat as much, so their bodies retain heat without them knowing it. This puts them in real danger.

"Our advice is simple - stay out of the sun where possible, dress in light clothes and stay hydrated."

Relaxed dress codes

A leading union, the TUC, has urged employers to relax dress codes as the temperature rises.

The TUC said the best way for staff to keep cool inside was for workers to wear more casual attire in the office, perhaps coming in jacket and tie-less, or wearing shorts.

TUC general secretary Brendan Barber said: "It's no fun working in a baking office or factory and employers should do all they can to take the temperature down.

"Clearly vest tops and shorts are not suitable attire for all front line staff, but those not dealing with the public should be able to discard their tights, ties and suits. We're calling on bosses to let their staff loosen their collars and cool down while the heatwave continues."

Tube and buses unbearable

Conditions will be the worst on public transport, with temperatures reaching 52C on buses and 47C on the Tube yesterday, according to an Evening Standard report.

London mayor Ken Livingstone last month warned that global warming could cause "loss of life" if a train broke down underground in a few years' time.

A groundwater cooling system is currently being installed for trial at Victoria station. Cold water already pumped out of the station will be used to cool hot air on the concourse and platforms.

The heat is due to high pressure sitting over the UK, and with very dry air, the heat keeps rising.

A heatwave warning has been issued until Friday, but thundery showers are expected to bring some relief tomorrow, with temperatures cooling to 30C.

Londoners save waterMeanwhile, Thames Water has praised Londoners for saving water this summer.

Demand for water in the capital dropped by around 7.5 per cent, or 176 million litres every day, the under fire water company said.

Thames Water customer service manager Duncan McCombie said the water saving was particularly noticeable on hotter days.

"We want to say a big thank-you to all our customers who have been saving water during the drought, but with July temperatures soaring we do very much need them to keep up the good work.

"We know June's fall in demand can't simply be due to the hosepipe and sprinkler restrictions, because only four out of every 10 of our customers own a hosepipe.

"It just goes to show that if everyone makes small changes to their daily routines, such as only switching the washing machine or dishwasher on when they are full, it can help make a big difference."