Parts of Britain have been warned temperatures could rise above 35C (95F) this week, as holidaymakers are urged to stay out of the sun amid extreme hot weather that is gripping northern Europe.
Monday was the hottest day so far of 2018 with a high of 33.3C recorded at Santon Downham in Suffolk. But it is set to get even hotter, with temperatures expected to peak on Thursday and Friday thanks to a plume of air dubbed the Mediterranean Melt.
Temperatures reached a high of 31.4C (88.5F) on Tuesday as the heatwave continued across vast parts of the UK.
The Met Office said the UK hotspot was Cavendish, Suffolk, with the temperature there 23C (42.1F) higher than the lowest temperature on Tuesday: Drumnadrochit, near Loch Ness in the Highlands, at 8C (46.4F).
Hurn, Dorset, saw the most sun with 13.9 hours, while Dundrennan, Dumfries and Galloway, was the wettest with 7mm of rain.
Temperatures hovered around 21C (70F) in parts of East Anglia and London around midnight on Monday, which is around the average July day time temperature for the region of 19-23C (66-73F).
Becky Mitchell, Met Office meteorologist, said temperatures of 35C were forecast for Thursday in East Anglia and London, adding: "There's potential it could go even warmer than that."
She said the climbing temperatures were due to warm air coming up from France combined with high pressure across the country.
Video: Met Office forecast for Tuesday and week ahead
With officials warning people to stay out of the sun or at least avoid being in the sun between 11am and 3pm until Friday, tourism bosses have expressed their fury over fears it could impact their industry.
Malcolm Bell, chief executive of Visit Cornwall, said: "It’s nanny state with the biggest capital N you could possibly print."
However, a respite from the heat could come by the end of the week, when thunderstorms are expected in eastern areas.
An amber "heat health watch" warning has been issued for parts of England. These are issued when temperatures are predicted to hit 30C (86F) during the day, and 15C (59F) at night, for at least two consecutive days.
There is a 90 per cent possibility of heatwave conditions between 9am on Monday and 9am Friday in parts of England, mainly in the south and east.
What is causing hot weather and cloudless skies?
The prolonged warm, dry weather is caused by an area of high pressure sitting to the west of Britain, leaving the country basking under cloudless skies.
Professor Peter Stott, Met Office science fellow in attribution, said global temperature rises were fuelling heatwaves, and climate models had been predicting an increase in extremely hot spells for more than a decade.
"It's coming true before our eyes," he said.
Mr Stott added: "It's quite interesting to compare the temperature anomalies with 1976.
"Back in 1976 we were having this prolonged heatwave, but much of the globe was pretty average. Now if you look at the globe, it's pretty warm."
He said the chances of having so many heatwaves across the globe this summer "must be really low" without climate change."We are loading the dice towards extreme weather," he said.
Britain tries to keep cool in heatwave, in pictures
Sales of fans soar as families struggle to cope
As householders seek to keep their cool in the prolonged heatwave, sales of fans and air purifiers are soaring.
John Lewis said sales of electrical cooling products were up 315 per cent week-on-week as weather forecasts showed no relief from the high temperatures for at least a fortnight.
Lighter low tog duvets are up 39 per cent on last year, while sales of dresses at the department store chain are up 40 per cent since the beginning of the month, and charcoal barbecue sales are up 116 per cent on last year.
Halfords has seen a surge in spending on heat-related products, with sales of car sunblinds up 280 per cent compared with last year and barbecue sales up by 723 per cent on last week.
Pharmacy chain Superdrug said it had had to reorder more stocks of of its mini fans after they sold out. It also reported that sales of tanning and bronzing products were up 26 per cent alongside a 112 per cent increase on sunscreen compared with last year.
UK's driest first half of summer since 1961
The hottest July day on record is 36.7C (98F), which was reached at Heathrow on July 1 2015.
The Met Office said several places have had 54 consecutive dry days, starting May 30, including a few which have had less than 1mm of rain in the entire 54-day period - the longest spell since 1969, when 70 days passed with no significant rainfall.
The longest run of days with no rain at all this summer so far is 48 days at Brooms Barn, near Bury St Edmunds, since June 5.
A spokesman said: "It's the driest first half of the summer since 1961.
"For the UK as a whole, we've only seen about 20 per cent of the rainfall we'd normally expect throughout the whole summer. Parts of southern England have seen only six per cent."
From Ireland to Tokyo: Heatwaves across world
It comes as weather extremes including record temperatures, heatwaves and drought, are being seen across the northern hemisphere in the first half of summer, hitting health and agriculture and causing dangerous wildfires.
An intense heatwave hit Japan, with record highs of 41.1C in Kumagaya and 40.8C in Oume, both near Tokyo, on Monday, as the country struggles to recover from its worst flooding and landslide disasters in decades.
In Europe, a second Climate Watch advisory was issued for July 19 to August 6 covering an area from Ireland to the Baltic States and Scandinavia, with temperatures as much as 10C above average in some places in the first week.
The soaring temperatures in northern Europe are accompanied by drought and a risk of local thunderstorms, wildfires and harvest losses, the World Meteorological Organisation (WMO) said.
Twin wildfires raging through popular seaside areas near the Greek capital Athens have torched homes, cars and forests and killed at least 49 people.
An extended heatwave in Scandinavia has seen temperatures top 30C in the Arctic Circle, and Sweden reported around 50 forest fires burning in mid July.
In Ireland heatwaves were recorded at 15 weather stations, with five or more consecutive days with temperatures above 25C, and an absolute drought at all its stations, the WMO said.
Heat could send pensioners 'over the edge'
As Britain basks in glorious sunshine for yet another week, medical professionals have warned the heatwave risks sending pensioners with underlying health issues "over the edge" as A&E departments reach peak levels.
GP Dr Hein Le Reux told the BBC: "It's really serious because older people have underlying problems and are perhaps on many tablets, and the hot weather just tips them over into not being able to cope.
"We're seeing a spike in our A&E demands. Departments locally have been the busiest on record."
The searing temperatures also prompted the TUC to call on firms to allow informal dress to keep office workers cool.
Heatwave could prompt start of 'faux autumn'
Experts have warned the heatwave risks bringing on a faux autumn with prematurely ripening fruits and browning leaves.
The Woodland Trust said the unprecedented hot and dry weather is causing blackberries and other hedgerow fruits to mature two months ahead of their usual growth pattern in some parts of the country, spelling danger for the animals that feed on them.
The Woodland Trust said it had received dozens of reports of blackberries or bramble and rowan berries ripening, with the earliest sightings two months earlier than the usual date towards the end of August.
It also warned that leaves on trees may begin to change colour far earlier than usual in a bid to preserve water, making them susceptible to threats such as pests and disease.
The trust said that if the current hot, dry weather continues, the lack of rain could lead to berries being smaller or dropping from trees and shrubs altogether, threatening migratory birds such as fieldfares and redwings which usually arrive in the UK in October
Weather map for Tuesday and week ahead
For the latest UK weather news, click here.