About 2,500 Indian nationals, mostly hailing from Punjab, are seeking political asylum in Britain forcing the government to tighten visa regimes.

Stringent measures, including a two-year prison term, await those who destroy their travel documents.

The modus operandi in several such cases ha a pattern. Such persons have a transit halt at Heathrow Airport where they destroy their passports, claim they are persecuted back in India and seek asylum in UK.

"Their applications seeking asylum are pending," a senior British official told a group of visiting Indian journalists.

Luring prospective aspirants with job offers, unscrupulous travel agents from India have also used this route to make money.

In August this year, five of a team of visiting women cricketers went missing, apparently in search of greener pastures. Three have since returned but the whereabouts of the remaining two are still not known.

Indians continue to be among the largest asylum seekers in the UK. There are sizeable numbers in this category from Somalia, Zimbabwe, China, Pakistan, Iraq, Iran, Turkey, Afghanistan and Congo.

"It is a major problem," noted industrialist Lord Swraj Paul said. He added this was one of the primary reasons for the introduction of the transit visa by the British government.

Put into force on October 15 this year, it stipulated that nationals of India, Angola, Bangladesh, Cameroon, Lebanon and Pakistan will need visas to travel through the UK.

Previously, people from these countries required visas to visit the UK but were able to travel without one if they passed through on their way to a third country.

"The tightening of the rules is in response to attempts by some of these nationals to circumvent the UK's immigration system," the Home Office said.

"We are responding to intelligence that some nationals of these countries are using transit visas to flout our immigration controls and either enter the UK illegally or make unfounded asylum applications," it said.

British authorities clarified that in certain categories transit visas will not be required. This will not apply to those having a valid visa for entry to Canada or the US and a valid ticket to travel to these countries.

Diplomats and those holding official passports, persons having US Green Card, Canadian Permanent Resident Cards have also been exempted from this requirement.

Earlier this week, British Home Secretary David Blunkett unveiled a package of asylum measures. For the first time, a criminal offence will be laid out if one arrives in Britain without a good explanation for not having any travel documents.

It will also become a criminal offence to refuse to cooperate with getting a new set of documents to prevent deportation.

Significantly, Blunkett brought relief to 15,000 asylum families who have been waiting for more than three years. They have been allowed to live and work in Britain.

The measures plug benefits made available to people seeking asylum. The government proposes to end support for families unwilling to return home, provide for only a single appeal for failed asylum applicants and arm the authorities with new powers to raid unqualified immigration advisers.

The British home office has sent out a stiff warning that those assisting illegal immigrants could face a five-year prison term.

Expressing its determination to come down on criminals of Asian and Afro-Asian origin, Britain has also announced that refugees or asylum seekers who commit serious offences would be stripped off their right to remain in the UK. The list of offences include violence, sex-related ones, terrorism and drug crimes.

The government already has powers under the Nationality, Immigration and Asylum Act, 2002 to ensure that an individual sentenced to more than two years imprisonment will have their asylum claim turned down. This new power extends these provisions to all refugees or asylum seekers convicted of a serious offence.

Hard-pressed Indian high commission officials are also facing a tough task in dealing with such cases.