Getting stuck on the Tube alongside some unwanted gases is, unfortunately, a regular fate for the average Londoner, but it seems we might need to worry about more serious circumstances than the odd bout of a neighbouring passenger’s wind. The Department of Transport will soon be releasing gas onto the underground between peak travel times to test the speed that poisonous gases could spread through the network. Don’t worry, the poisonous part is hypothetical. Tube-users won’t be able to see, smell or taste the gas, let alone be harmed by it. But that’s not to stop you borrowing a gas mask for good measure – any excuse for fancy dress, right?