While the exact motive of the Ariana jet hijackers remains unclear, speculation has settled on the issue of asylum.

There is a suspicion the hostage-takers were seeking sanctuary from the Taleban regime in Afghanistan, which has a known record for persecuting dissidents.

One report suggested they were demanding immunity from prosecution and the right to set up an Afghan political opposition in the UK.

However, David Stevens, chief constable of Essex Police, said he was not aware that the matter of asylum had been discussed at all during the four-day stand off.

If the hijackers do seek refugee status, any application would have to come after all other legal proceedings have been completed.

Normally, foreign nationals convicted of crimes in this country would be deported at the end of their jail term. But the UK is obliged under international law to consider any asylum claim.

However, the hostage-takers may face a long prison sentence beforehand. Britain takes a tough line on such crimes and previous hijackers have served sentences for up to nine years.

No guarantees

The police have said no deal was done with the hijackers about asylum or anything else.

This is not the first time gunmen have forced their way into Britain to file for asylum.

Six members of a gang which hijacked a Sudanese passenger jet in 1996 are still living in the UK, awaiting a decision on their claims.

A man involved in a 1982 Air Tanzania hijack was granted asylum here having served two years of a three-year sentence.

As it stands, about 60 passengers freed on Thursday morning have already requested refugee status.

Like all asylum seekers, their cases will be treated on an individual basis.

According to international convention, each will need to show a "well-founded fear of being persecuted for reasons of race, religion, nationality or membership of a particular social group or political opinion".

The Home Office has set itself a target of deciding all cases within two months, although asylum seekers have a number of appeal options at the end of that time.

4,000 asylum seekers

But Labour MP Robin Corbett, who serves on the Home Affairs Committee, said the hostages would probably find it hard to sustain their claims since they had initially boarded an internal flight.

There has also been speculation that some of the "hostages" were complicit in the hijacking, seeing it as a flight to freedom.

Last year, 3,980 people sought asylum in the UK from Afghanistan - a small number of claims were recognised and somewhat more were given exceptional leave to remain.

Under the terms of the Immigration and Asylum Act, which comes into force in April, the Afghans will have to get by on vouchers for food and other essentials rather than cash handouts.