ITV News Consumer Editor Chris Choi reports on how the heatwave is affecting transport services across the country on the second day of travel disruption
Weather forecasters and health experts are warning the public over soaring temperatures as the "extreme" heatwave continues to sweep across the UK.
Britain's first ever red extreme heat warning came into effect on Monday and will last until Wednesday, with temperatures likely in the high 30s and predicted to top 40C for the first time ever in some parts of England.
Several weather records were broken on Monday, which was the hottest day of the year so far, the warmest night on record, and the third hottest day on record with temperatures hitting 38.1C in Suffolk's Santon Downham, while Wales saw its hottest day on record.
Railways and roads will be affected by the heatwave and travellers are urged to be prepared for disruption and avoid travel all together if possible.
Here's what to expect and how to prepare over the coming days.
More than a dozen train companies are urging Britons not to travel early this week, while cancellations are in place to cope with the extreme heat.
The hottest railway track reached a scorching 62C on Monday, as the Transport Secretary admitted it will take decades to upgrade existing lines to be more resilient.
Grant Shapps conceded the UK’s transport network cannot cope with the extreme heat, saying that the Victorian-era infrastructure “just wasn’t built to withstand this type of temperature”.
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And most routes across England and Wales will be affected again by the hot weather on Tuesday, which has set a new all-time record in the UK, with customers told only to travel if “absolutely necessary”.
Speed restrictions were in operation to avoid any damage being made to the tracks and to prevent rails from buckling. These speed restrictions could more than double journey times for passengers, the chief spokesman for Network Rail has said.
There are no services in and out of Birmingham New Street station after a fault with electrical overhead lines - leaving five trains stranded and unable to reach platforms.
All services to and from London Euston were suspended as emergency services were called to a lineside fire.
The blaze was caused after 25,000 volt overhead electric cables came down in Harrow, Network Rail said.
Part of the East Coast Main Line will be closed on Tuesday - the routes between York-London and Leeds-London and all stations between. The service north of York will be running.
Tickets can be deferred to Wednesday or Thursday.
A total of 21 operators – ranging from Transport for Wales and Gatwick Express, to the Transpennine Express and Southern – said they will be running a slower service on Monday and Tuesday after National Rail implemented speed restrictions across its network.
Services between Manchester Piccadilly and Sheffield were suspended until further notice on Monday and customers were advised not to travel.
Southern, South Eastern, Thameslink Southern, South Western Railway and Great Western Railway are among those that will be running a significantly reduced service and passengers should only travel if essential.
Merseyrail said the number of trains running and journey times will be “seriously affected”, with some routes closed completely.
South Western Railway and Great Western Railway are also warning of short notice cancellations.
There will be no Thameslink or Great Northern trains running in any location north of London, from London Blackfriars via St Pancras, or from London King’s Cross or London Moorgate on Tuesday. This also affects trains running to and from Cambridge, Bedford, and Peterborough.
There will also be no train service on the East Coast mainline - the route from London to destinations like Peterborough, Leeds and York on Tuesday.
Transport for London (TfL) said London’s rail network would also be running a reduced service on Tuesday due to safety restrictions put into place to deal with the heat.
Those who have to travel are encouraged to check their journeys on the National Rail website before setting off and taking water with them to stay hydrated.
Refunds will be given to any passengers who booked journeys on Monday and Tuesday who rearrange travel for later in the week.
The chances of services returning to normal by midweek will also depend on any “damage that the weather does to the infrastructure” over the course of Monday and Tuesday.
Speaking to BBC Radio 4’s Today Programme on Monday, Mr Kelly said the decision to cancel some services were not taken "lightly" but added "we’ve not been faced with these exceptional temperatures before.”
He added: “We’re spending hundreds of millions of pounds a year on making the railway more resilient but ultimately faced with weather like we’ve never faced before, the infrastructure will suffer so we’ve had to put in place arrangements.”
Transport for London (TfL) said around 1.06 million entries and exits were made by London Underground passenger on Monday up to 10am.
This is down 18% compared with the same period last Monday.
The AA warned of roads melting and tyres bursting during the heatwave.
Some local authorities sent out the gritters late last week to put sand on roads to try to prevent the road surface from melting. They remained on stand-by to spread light dustings of sand on melting roads.
The RAC anticipated that the number of vehicle breakdowns on Monday and Tuesday could be up to a fifth higher than normal.
The AA and North West Ambulance Service have been advising that there is a greater danger of tyre blow-outs in extreme temperatures and have suggested drivers check their tyre pressures – when the tyre is cold – before setting off on their journeys.
They have also urged people to drive earlier in the day to prevent engines from overheating and advised people to carry at least one litre of water per person in the vehicle.
Figures published by location technology firm TomTom show the level of road congestion at 9am on Monday was lower in most UK cities than at the same time last week.
In London, congestion levels fell from 53% on July 11 to 42% on Monday.
In Birmingham they were down from 46% to 43%, in Manchester they decreased from 45% to 37% and in Glasgow they dropped from 17% to 12%.
Edmund King, AA president, said: “The extreme temperatures could be dangerous if you breakdown or get stuck in congestion. Ensure you have enough fuel or electric charge to keep your air-conditioning running.
"The heatwave could cause considerable problems for many older vehicles without air-conditioning or recent servicing, with both the car and occupants over-heating."The Department for Transport is in touch with port operators, highways agencies and the police to “check their contingency plans”.
Travellers at Luton airport faced disruption on Monday as a runway was closed for urgent repairs after the hot weather damaged the tarmac.
Flights were suspended due to what the airport described as a "runway defect".
"Following today's high temperatures, a surface defect was identified on the runway. Engineers were called immediately to site and repair works are currently in progress to resume operations as soon as possible," the airport said in a statement on Twitter.
It reopened to departing and arriving flights shortly after 6pm on Monday.
Guy Hobbs, Editor of Which? Travel, said: "If your flight is cancelled because of the heatwave, you will be entitled to a refund or rebooking, including with other carriers if necessary.
"However, you are unlikely to be owed additional compensation as extreme weather is considered an extraordinary circumstance, outside of the airline's control."
RAF Brize Norton will remain closed on Tuesday, it is understood.
An inspection and assessment is due to be carried out later and again on Wednesday morning.
It was announced on Monday that flying activity was halted at the RAF base in Oxfordshire “during this period of extreme temperature” and that aircraft would be using alternative airfields.
A spokesperson for Heathrow Airport, meanwhile, said things were flowing smoothly, with no major problems despite the intense heat.