It's good news for cattle, but bad news for commuters, as the heatwave currently hitting London will mean the temperatures on some tube trains tomorrow will exceed the legal limit for transporting cattle.

In London, temperatures could peak at 33 degrees, and thermometers are set to reach breaking point in other southern parts of the country and in central regions.

With the outside temperature this high, it's going to be even warmer on the Central line, which has been named as the hottest route on the underground system.

Due to its depth and the difficulty of installing air conditioning on the 115-year-old line, Transport for London and research by CityMetric both confirmed that the Central line will be the hottest on the tube network.

According to EU rules on the welfare of animals during transport, ventilation inside cattle trucks must ensure that the temperatures remains between five and 30 degrees. Any higher or lower, and farmers could get in trouble.

In pictures: Tube strike April 2014 Show all 5 1 /5 In pictures: Tube strike April 2014 In pictures: Tube strike April 2014 Tube Strike Commuters travel on the Northern Line of the London Underground which is running a limited service due to industrial action on April 29, 2014 in London, England. Getty Images In pictures: Tube strike April 2014 Tube Strike Commuters at Stratford Underground, Overground and DLR Station in east London, on the first day of a 48 hour strike by tube workers on the London Underground over ticket office closures. PA In pictures: Tube strike April 2014 Tube Strike Commuters prepare to travel on the District Line of the London Underground during strike action on 30 April, 2014 Getty Images In pictures: Tube strike April 2014 Tube Strike Commuters attempting to board a full underground train on day two of a 48 hour underground train strike on 30 April, 2014 Getty Images In pictures: Tube strike April 2014 Tube Strike Commuters wait at Victoria tube station for limited service trains in London, Britain, 29 April 2014. EPA

Unfortunately for London commuters, these EU regulations don't apply to humans, meaning the temperatures on the Central line, which often reach as high as 35 degrees during the hot summer months, are just a fact of life.

With the Met Office predicting that Wednesday could be the hottest day of the year, it's likely that the temperatures on the line will easily rise higher than 30 degrees.

David Waboso, Capital Programmes Director at London Underground, said: "As part of our plans to improve every single journey we are making real headway towards cooling the Tube."

“However, there is still work to do. Cooling the deeper lines of the Tube is a big engineering challenge, but we’re making significant steps forward for the next generation of Tube trains on the Piccadilly line, we will include a requirement for air conditioning.”

Under improvement plans, air-conditioned trains will make up 40 per cent of trains on the network by 2016.