- It is one of the most memorable lines in movie history. As the air around him is rent by explosions and the whiz of bullets, Colonel Kilgore stands nonchalantly with hands on hips, sniffs the acrid breeze and declares: 'I love the smell of napalm in the morning.'
Now actor Robert Duvall
's famous scene from the Vietnam epic Apocalypse Now could be re-enacted in millions of teenagers' bedrooms - thanks to technology that will allow computer games consoles to release the stench of war.
The Ministry of Defence is part-funding a project in which foul smells are released into the air during training videos so that recruits literally learn to sniff out trouble.
If the technology proves a success, it is expected to be taken up by manufacturers of top-selling consoles - such as the Xbox 360 and PlayStation 3.
The team of psychologists and computer engineers developing the technology, on behalf of the British Army, plan to bombard troops with odours ranging from body sweat to diesel exhaust.
The aim is to teach recruits that the presence of some smells and absence of others could indicate danger.
At the moment, the technology is still in its infancy. But the scientists say it will soon be possible to design games in which the screech of tyres during a high-speed chase will automatically trigger the release of the smell of burning rubber.
Professor Bob Stone
, research director of the Human Factors Integration Defence Technology Centre (HFIDTC) at Birmingham University, believes the technique could save soldiers' lives.
'Let's say a unit is passing through a village somewhere in the Arab world where there is always the smell of cooking meat,' explained Professor Stone.
'On the day in question that smell is not there. That could mean the village has been evacuated because the enemy are using it as a base from which to attack British troops. Smell is the most underrated and underused of our senses.
'If we rely only on sights and sounds, we are in danger of closing our minds to what is going on around us. And for a soldier, that can mean the difference between life and death.'
His 'scent delivery system' consists of a compressed air chamber with four fans and eight compartments, each of which holds a pot of wax, chemically impregnated with a particular odour.
Those in Professor Stone's armoury so far include cordite, burning electrical wire, weapon fire and harbour and hospital smells, though other unpleasant stinks, such as mildew and cat urine, will be added to the list.
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.'