Airlines are preparing to launch a crackdown on outbreaks of air rage, blaming the terror strikes on America for sparking a massive increase in vigilantism and violent incidents on aircraft.

The International Civil Aviation Organisation has drawn up draft legislation which would allow disruptive or suspicious passengers to be arrested and prosecuted anywhere in the world. The introduction of 'air marshals' - armed security guards - on flights and a complete ban on alcoholic drinks are also being considered.

Professor Graham Lucas, a consultant in aviation psychiatry, will explain the pressing need for an alcohol ban at a Royal Society of Medicine conference on the health risks of international travel tomorrow.

'Alcohol is banned at major football and rugby grounds - and people are out of doors there,' he said. 'Locked up in a fuselage, consuming all that drink - that is a real recipe for disruption. That is why we need a ban.'

Shane Enright, civil aviation secretary of the International Transport Workers Federation, believes the situation has worsened following the attack on the twin towers. 'It has become increasingly difficult to differentiate between a case of air rage and a terrorist event,' he said.

In other words, a domestic tiff, fuelled by drink, is more likely to be interpreted as an act of terrorism. Estimates suggest there could be more than 6,500 cases of air rage in the 12 months following 11 September, compared to 5,416 in 1997 and 1,371 in 1994.

It is this rise that has led to the creation of the international treaty - which is to be introduced in the next two months. It will give police and courts the power to prosecute all incidents on any flight from any country.

The new directive by the International Civil Aviation Organisation, the world governing body regulating major airlines, will supersede existing international law which states that the country of registration of an aircraft has responsibility for illegal acts on board.