Michaela Avei, 19, a student from Kensington, said: "I swallow it rather than chuck it on the ground and I don't see why I should pay for other people's mess. It would make me angry if the price went up significantly because of this." Giagano Bovino, 21, a student from Knightsbridge, said: "If we charge more so we fund the clean-up we only encourage people to throw it on the ground."