Those who had to stay in the city flocked to parks to sunbathe

Despite a slow start, partly due to cloudy skies and isolated showers mainly in the north, traffic jams were reported on many coastal routes.

Temperatures were expected to rise even further later in the day.

Traffic hotspots included the M25 in Kent and the M23 in Sussex, but no major accidents were reported.

However the hot weather has taken its toll in Essex, where a man is believed to have drowned while swimming at Harwich.

Police, who are still identifying the body, have warned beach-goers against swimming alone in the area.

Traders' joy

Meanwhile, traffic was said to be "heavy going" particularly in England's south-east as people flocked to the seaside at Brighton, Margate and Eastbourne.

Peter Avey, the manager of a cafe and restaurant on Brighton beach, was ecstatic.

This weather has saved our lives, it was getting a bit desperate Peter Avey Brighton caf� owner

"This weather has saved our lives, it was getting a bit desperate," he said.

"It is very busy and people are having a great time."

In the West Midlands a rainy morning was followed by sunshine, with shoppers flocking to the city centre to take advantage of the summer sales while spectators enjoyed a full afternoon's play in the second Test at Edgbaston.

In London, thousands sunbathed in St James's Park by the water, some playing in the fountains, while a brass band played.

Stallholder Miguel Rodriguez had a busy day, selling 500 ice-creams by 3pm.

Earlier in the day light showers and a few heavier downpours affected the south-east coast of Scotland and parts of northern England.

But the Met Office duty weather forecaster told BBC News Online temperatures were still far above average.

The mixed picture would continue next week, he said.

He added that nights would feel rather uncomfortable, with temperatures hovering at 18 or 19C.

'Horrendous queues'

A spokesman for AA Roadwatch said: "We are receiving about double the amount of information we would normally receive on a Saturday.

"The weather is so nice people don't want to stay at home - they want to go out to the seaside," he added.

"Coastal routes are a major problem."

"Horrendous queues" were reported on the M25 clockwise from Potters Bar junction 24 to junction 1A, while the A133 between Weeley and Clacton-on-Sea in Essex was particularly busy.

In view of this weekend's record-high temperatures, largely due to the so-called "Azores high", an area of high pressure over the Atlantic, the government issued new heatwave survival advice intended for vulnerable people.

The NHS and other public bodies will act in response to four levels of alert, ranging from Awareness to Emergency, in an attempt to prevent the "excess deaths" which occurred in Britain during last summer's heatwave.