Record UK temperatures will bring widespread disruption to the UK's transport network today and tomorrow.
The UK’s first red extreme heat warning covers a large swathe of England from London to Manchester and York for both Monday and Tuesday and the UK Health Security Agency issued a heat health warning at level four, which is described as a “national emergency”.
Last night, the boss of LNER, David Horne, updated passengers, warning of severe disruption on the East Coast main line, Aberdeen's arterial route to London.
The line will be closed between York and London King's Cross tomorrow.
"Please do not travel on Tuesday," Mr Horne said, stating that people should only travel today if the journey "is absolutely necessary".
He added: "The rail industry has taken the very difficult decision to close the East Coast main line between York/Leeds and London on Tuesday when temperatures are due to peak at 39-degrees.
"I’m sorry if this will disrupt your journey plans but the safety of everyone must come first."
Network Rail said speed limits would be imposed on every line in the country, doubling journey times in many areas. The restrictions mean most trains will have to travel at between 60mph to 90mph, compared to normal speeds of 100mph to 125mph.
A journey from King’s Cross that would usually take two hours will on Monday take more than four, a spokesman said. In certain areas more susceptible to the heat, trains will be forced to a 20mph crawl.
Worker fears
Meanwhile, a union has called for a legal limit on how hot it can be in a workplace as a red warning for extreme heat begins.
The GMB union said workers should not have to contend with temperatures any higher than 25C, as forecasters predict a record high of 41C (106F) in England.
There is currently no law in the UK or Ireland which states any given temperature is too hot or cold to work.
But workplaces should ideally be at least 16C - or 13C if the job is mostly physical - according to the Health and Safety Executive (HSE).
Responding to the call for a legal maximum, an HSE spokesperson said: "There is no maximum workplace temperature because every workplace is different.
"Responsibility to make workplaces safe and healthy lies with employers. Workplace temperature is a hazard that comes with legal obligations for employers like other hazards."