As temperatures in London soar to 36°C, millions of commuters will be dreading their journey home. But just how hot is your commute? As the mercury crept up earlier today, the Daily Mail's Senior Science & Technology Reporter, Wiliam Hunter, set out along some of the most popular London Underground lines and bus routes, armed with a thermometer. And the results might make you wish you had worked from home – particularly if your journey includes a trip on the Victoria Line. This line – which includes popular stops such as Brixton, Oxford Circus, and Victoria – topped the chart in our tests, clocking in at 35.2°C – around 4°C hotter than it was above ground.For comparison, government legislation rules that you can't legally transport cattle when temperatures climb above 30°C – a limit exceeded by almost every line in our tests.And it isn't just the heat you need to worry about. We also found that the humidity inside a busy carriage ranged between a swampy 60 per cent and a borderline tropical 80 per cent. As the mercury crept up earlier today, the Daily Mail's Senior Science & Technology Reporter, Wiliam Hunter, set out along some of the most popular London Underground lines and bus routes, armed with a thermometer