The government is in discussions with security companies and Britain's airports to lift the ban on liquids being carried in hand luggage as early as next year.

Technology already deployed at Heathrow's new Terminal 5 can automatically detect the presence of liquids in carry-on bags. Now, government scientists are running tests to see if the scanners can be adapted to pick out those that are harmful.

"The technology is there, which will allow these scanners not only to test for liquids but also to determine if those liquids are dangerous or not," said a security industry source. "At the moment, that technology is being tested by the security services and when they are happy that it works, the ban will be lifted."

The aviation industry is keen to see a change in the restrictions, brought in after intelligence experts believed they had foiled a plot to blow up airliners with liquid bombs in August 2006.

Yesterday, Virgin Atlantic said the "time may now be right" for a change in the security rules.

The renewed pleas come after the trial of eight men over the alleged plot. None of the group on trial was found guilty on the airliner charge but three were found guilty of conspiracy to murder. They had stood accused of using soft drinks bottles to disguise homemade bombs that would be used to blow up planes flying across the Atlantic.

Fears from security forces that a similar attack could be attempted saw severe restrictions on hand luggage immediately introduced.

The current restrictions, which limit the volume of liquid that can be carried by travellers in their hand luggage, has cost airport operators tens of millions of pounds to enforce.

Airlines have complained that the rules make the UK's hubs less attractive to passengers. Analysts put the total cost of the liquid bomb plot to the industry at as much as £200m.

Current rules dictate that bottles containing more than 100ml of liquid cannot be carried in hand luggage, while the amount of hand luggage that can be restrictions, which limit the volume of liquid that can be carried by travellers in their hand luggage, has cost airport operators tens of millions of pounds to enforce.

Airlines have complained that the rules make the UK's hubs less attractive to passengers. Analysts put the total cost of the liquid bomb plot to the industry at as much as £200m. The hand luggage restrictions dictate that bottles containing more than 100ml of liquid cannot be carried and only one bag is allowed.

BAA, which operates the UK's main airports Heathrow, Gatwick and Stansted, had to recruit 3,000 extra security staff to cope with the restrictions. It puts the total cost of the measures in the "tens of millions". "We have been calling for a review of the rules for a long time, along with many other airlines and airport operators," said Paul Charles, Virgin's head of communications.

"When you go to airports at the moment, you can see the confusion, with many people still bringing too many liquids. We believe that things could be made simpler for the public, to ensure the same rules are in place wherever you are travelling from in the world."

Four UK airports including Heathrow have bought scanners that will detect dangerous liquids and more are on order. It is believed the Government will not lift the restrictions until all major airports have the new technology.

ButThe Department of Transport said it took its lead from advice given by the joint intelligence analysis centre. It added that the recent bomb plot court case had proven that potential terrorists were already capable of creating bombs from domestic items.

"Aircraft could be vulnerable to such devices so we are right to continue to require the restrictions for liquids in hand luggage," said a spokeswoman.

"We are also right to require these restrictions internationally, as we are all at risk. We continue to work with international colleagues to develop technological detection methods which could ease the restrictions."