Tube + football fans = deafening squish

First time catching the tube on a game day - Tottenham vs Chelsea. The tube started off predominantly Tottenham supports who happily sang and drank (still not sure if legal or just accepted). Whether it was some young guys, peroxide blonde in heels or an old guy sitting down - everyone sang along. Some Chelsea fans got on and the volume increased sigficantly until both sides realised they were singing the same little ditty! There were an awkward few seconds of silence until they were off again!