Rush-hour commuters demanded air conditioning across the entire Tube network as they battled “sauna-like” conditions.
Passengers said the infrastructure needed to be improved as temperatures on the Central line smashed the 30C legal limit for transporting livestock.
Sally Vjalo, 38, said: “Given how much money they spend on trains you would have thought they could have got some air conditioning. It’s like a sweatbox on there.”
The Standard recorded temperatures of 36.6C on the Central line during last night’s rush hour — with forecasters warning of even hotter weather to come today. Jessica Shand, 29, who works in beauty PR, said: “I felt faint in there it was so hot, it was suffocating.”
The Met Office said there was a 60 per cent chance the mercury could rise above the current all-time UK record of 38.5C today, after temperatures hit 32.4C at Heathrow yesterday. Air-conditioned Tube trains run on the Circle, District, Hammersmith & City and Metropolitan lines, which cover 40 per cent of the network.
Transport for London said there were also “enhanced tunnel ventilation systems” on both the Victoria and Jubilee lines, while more than two thirds of the Overground fleet is air-conditioned, as well as all trains running between Paddington and Heathrow.
However, it admitted it may need to introduce speed restrictions on the Tube as a precaution to cope with today’s extreme heat.
Mark Evers, director of customer experience for London Underground, said: “We might need to reduce the speed of our trains at some locations this week ... This may mean that your journeys take longer than usual.”
He added: “We advise customers to ensure they have water with them when they travel in order to stay hydrated, offer a seat to those who may need it, and, if they feel ill, to contact a member of staff at the next station or speak to the bus driver.”
Meanwhile, the heatwave has encouraged commuters to take to two wheels, with more than 40,000 Santander bikes hired every day this week.