During a demonstration in Professor Stone’s office, PhD research student Mark Blyth presses the 'raw sewage' smell button as 3-D images flash across the screen of a Toshiba laptop. Visitors look longingly at a gas mask hanging on a coat stand, wondering whether it will fit. A colleague from another department pops his head round the door, sniffs disgustedly and leaves with a muttered excuse.

Computer games are playing an ever-larger role in military training, partly because the devices used to operate battlefield technology systems increasingly resemble games console controls. Professor Stone believes the smells will prove attractive to the commercial sector. An American company called Trisenx is already working on something similar and I am sure there will be a successful crossover from military use to the home computer industry. Within three to five years there could be games on the market with smells designed to confuse or excite the player. When an alien appears on the screen, for example, he would have his own odour which would be instantly recognisable. Lieutenant Colonel Richard Eaton, spokesman for UK Land Forces, said: 'Anything that can add realism to a synthetic environment - whether it’s noise, heat or smells - will enhance the training experience.'