Rail passengers are being warned of lengthy delays as speed restrictions are enforced to prevent tracks from buckling in heat that has sparked wildfires across parts of Britain.
As the UK heatwave is set to last until the weekend, Network Rail has deployed “extreme weather action teams” across Britain in readiness for even warmer temperatures following Monday’s peak of 30.1C (86.1F) - making it the hottest day of the year so far.
The announcement came as wildfires took hold in parts of northern England and the Met Office issued its first “yellow” health warning for heatwave conditions of 2018 from Tuesday until Thursday evening.
In north Staffordshire, a search is under way for a missing child seen in distress in a lake. Two other youngsters managed to make their way out safely. It prompted police to urge people to be careful of the temptation to swim in open water in the hot weather.
Meanwhile, gardeners are being encouraged to “love your brown lawn” and avoid using paddling pools in a bid to preserve water - although utility firms described reserves as “healthy” and promised not to introduce hosepipe bans.
Forecasters expect the next few days to be even hotter, with the mercury set to rise to 33C (91.4F) later in the week.
It means parts of the UK are currently hotter than Athens in Greece, and on a par with Kuala Lumpur in Malaysia and Rio in Brazil.
The heatwave is set to last until the weekend, when temperatures are due to slowly fall.
Speed restrictions over fears for tracks in direct sun
Transport officials said rails under direct sunshine might reach 20C (68F) above the surrounding air temperature, causing the steel to expand - raising concern that rails will buckle as temperatures soar.
It means some routes, such as the line between London Waterloo and New Malden, will be subject to speed restrictions from 11am each day until Friday.
Network Rail's extreme weather action teams are being activated across Britain to monitor "vulnerable locations".
Andy Thomas, managing director of England and Wales at Network Rail, said: "On very sunny days, rails in direct sunshine can be as much as 20C above air temperature, causing the steel to expand markedly, and could - if not carefully monitored and action taken - buckle, causing travel disruption.
"Our engineers and specialist extreme weather teams are monitoring track-side temperatures at vulnerable locations and will, if necessary, introduce temporary speed restrictions during the hottest part of the day to keep trains running, albeit more slowly than normal."
Some sections of rails are painted white so they absorb less heat.
Slower trains exert lower forces on the track, reducing the likelihood of buckling.
'No one is immune to the power of the sun': Health warnings issued
Four areas of England - the North East, North West, West Midlands and Southwest - are now subject to the Met Office yellow health warning, meaning temperatures are expected to exceed heatwave thresholds, which range from 28C in the North East to 30C in the Southwest.
The Met Office said heatwaves can be dangerous for the very young, the elderly or those with chronic diseases.
Its warnings mean there is an 80 per cent chance of temperatures that could be a risk to health.
The yellow health warnings are for heatwave conditions between 9am on Tuesday to 6pm on Thursday.
The Local Government Association issued a plea not to neglect the elderly or vulnerable, more than 2,000 of whom died in England during the heatwave of 2003.
“The hundreds of deaths caused by temperatures each year are avoidable,” said chairman Izzi Seccombe. “No one is immune to the power of the sun.”
Sunshine sparks moor blaze visible for miles
The sweltering sunshine sparked a large moor fire in Saddleworth on Monday evening.
It could be seen 15 miles away in Manchester, with the blaze destroying at least two sheds and causing roads to be closed off.
Search resumes for missing child at lake
A search has resumed for a missing child who was seen in distress in a lake.
Police said two other children were able to make their way safely out of Westport Lake in north Staffordshire on Monday, after reports of three youngsters in difficulty in the water.
Emergency crews, including paramedics, firefighters and a police helicopter, were called to the scene at around 4.50pm.
An air ambulance also attended, but the search was suspended overnight due to fading light.
A Staffordshire Police spokesman said: "Emergency services are currently at Westport Lake in Stoke-on-Trent to resume the search for a missing child.
"Staffordshire Police, together with partners including West Midlands Ambulance Service, Staffordshire Fire and Rescue Service and specialist underwater teams, will recommence the search shortly."
The spokesman added: "All families involved are continuing to receive the appropriate support from specially trained officers.
"If you are visiting the location today, please show respect and allow the emergency services professionals to continue the search uninterrupted."
Water safety warning after man found dead
A man has died after he was seen struggling while swimming in a lake in Surrey. Police and the ambulance service were called to the lake in Nutfield after the man was seen to get into difficulties at 6.30pm on Monday.
A search was launched, including Surrey Fire and Rescue Service's water search team and Surrey Search and Rescue, and his body was found by a team of divers from rescue service Specialist Group International at 9.20pm.
A Surrey Police spokesman said: "The death is currently being treated as unexplained, although at this stage there is not believed to be any third party involvement and it is not believed to be suspicious. We are currently trying to locate the man's next of kin."
The force spokesman gave safety advice for swimming in open water and added that a number of youths had been swimming in the lake and behaving in an anti-social manner.
He said: "Bodies of water may look safe, but can hide dangers such as hidden currents, hazardous objects, pollution and cold water shock, which affects our ability to swim and reach safety if experiencing difficulties.
"It can also be difficult to gauge water depth - you could find yourself in unexpectedly deep water or injure yourself jumping into shallow water."
Let your grass go brown, gardeners are told
Water UK, which represents regional water companies, said heavy rainfall during spring had left aquifer levels robust.
However, Anglian Water issued a detailed list of dos and don’ts to prevent waste, including “leaving the sprinkler in the shed this summer”.
“Grass is extremely hard to kill - your lawn will soon bounce back and be vibrant and green again,” a spokesman said.
They added: “Forget the paddling pool and head to the beach...if you’ve already filled the paddling pool for the day, don’t empty it, you can save loads on your water bill by using gentle disinfectant tablets that keep the paddling pool water fresh for days.”
Failing that, Anglian customers are advised to use the water to “wash the dog”.
Mercury passes 30C - and it is due to get even hotter
On Monday, the hottest point of Britain was at Hampton, in London, where temperatures reached 30.1C - making it the hottest day of the year so far.
The previous 2018 record was recorded at St James's Park in central London, which reached 29.1 on April 19.
Meanwhile in Scotland, Achnagart in Ross and Cromarty boasted a temperature of 27.5C and the heat hit 25.3C in Castlederg in Co Tyrone, Northern Ireland, on Monday.
And high temperatures are expected to be beaten later this week- before dropping off at the weekend.
Merseyside is likely to enjoy the hottest weather on Tuesday, the Met Office said, with highs of 31C (87.8F) forecast.
Temperatures are set to rise, with a possible high of 33C (91.4F) on Thursday, meteorologist Alex Burkill said, soaring above the UK average for this time of year of 17.3C (63.1F).
The fine, hot weather looks set to continue into next month.
"At the moment it looks like that will be the general theme through much of July," he said. "Generally it looks like it will stay drier and warmer than average."
Forecasters said the hot weather is being caused by a jet stream looping to the north of the UK which has created an area of high pressure.
Weather map for Tuesday and week ahead
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