Rush-hour commuters on the London Underground sweltered in temperatures above the legal limit for transporting livestock on Thursday, the hottest day of the year so far.
Temperatures reached 35.7C (96.26F) on the Central Line, while the Bakerloo, Victoria and Jubilee all were several degrees above the 30C (86F) maximum for transporting cattle, sheep and pigs, the Press Association found.
Sweat-soaked passengers fanned themselves and gulped down water as the humidity in some carriages rose above 60%.
However commuters on the air-conditioned Circle Line enjoyed more tolerable temperatures of 29.4C (84.92F).
It comes after commuters battling “unacceptable” conditions were told they must wait more than a decade before air-conditioned trains arrive on some of the capital’s busiest routes.
In a Twitter Q and A with the Central Line chief, Chris Taggart, Giovanni Lepori said the heat was “reaching levels that are certainly dangerous for elderly people and children”.
He asked the official account: “What is being done to solve these unacceptable conditions for which we pay very high prices?”
The Central Line responded: “We’ve made improvements to the ventilation systems on the current fleet.
“New trains are coming in early 2030, under the Deep Tube Upgrade Programme which will be delivered with full air cooling systems.”
The response generated a flurry of scathing and sarcastic replies from irate social media users.
Just 40% of the tube network is currently served by air-conditioned trains, with 192 operating across the Circle, Hammersmith & City, District and Metropolitan lines, according to Transport for London (TfL).
Plans for air-conditioned Tubes on the Piccadilly, Bakerloo, Central, and Waterloo and City lines are in the pipeline as part of an overall upgrade, but are at least a decade away, a TfL spokesman said.
Between 5pm and 6.30pm on Thursday the Press Association recorded the following temperatures with a thermometer.
1. Central Line: 35.7C (96.26F)
2. Jubilee 33.8C (92.84F)
3. Victoria 33.4C (92.12F)
4. Bakerloo Line: 32.8C (91.04F)
5. Circle Line: 29.4C (84.92F)
A TfL spokesman said: “We completely understand that travelling can be uncomfortable during periods of hot weather and are investing millions of pounds to make the Tube cooler for customers.
“We are constantly working on new ways to keep the temperature down on the Tube and have doubled the number of fans on the network since 2012 as well as installing chiller units to pump in cold air.”
Cattle, sheep, pigs and goats, must be kept in compartments between 5C (41F) and 30C (86F) for export journeys over eight hours, according to the Department for Environment, Food, and Rural Affairs.
However, there is flexibility of plus or minus 5C to allow for exceptional circumstances.