Hong Kong military veterans who served in the British armed forces are going into battle against their former colonial ruler over their right to live in Britain.

With some locals increasingly anxious about Beijing's encroaching influence in Hong Kong, the veterans have become the latest group to put pressure on Britain to provide an escape route.

Three Hong Kong military veterans who say they were "abandoned" when the city was handed back to China in 1997 have applied for full British passports in a test case backed by some British members of parliament.

A petition for right of abode, which has garnered hundreds of signatures from ex-servicemen, has also been handed to 10 Downing Street in London, the official residence and office of the British prime minister.

"This is a right we deserve," 50-year-old former Royal Military Police officer Harry Wong, one of the three passport applicants, told AFP.

"We want to get back what is fair."

Wong says he applied for a British passport before the handover, but was unsuccessful.

Five hundred armed forces personnel were given British passports in the 1990s based on a points system -- but others were left behind, with campaigners saying the lower ranks were overlooked.

Former army dog handler Alain Lau, 52, said he was told by a local senior officer that he would not qualify for a passport.

"They just put us down here when they left," says Lau, who is a spokesman for the Campaign for Abandoned British-Chinese Soldiers Left in Hong Kong in 1997.

Concerns over China's influence have grown recently, with mass protests towards the end of last year after Beijing said that candidates for the city's next leader would be vetted by a loyalist committee.

Veterans say they now want an insurance policy for the younger generations of their families.

"One day, Hong Kong may not be the best for them. The political situation is quite chaotic now," said Wong, whose daughter is five years old.

- Plea for 'justice' -

British MP Andrew Rosindell is supporting the campaign and raised the issue in the British parliament in March, saying "it is only just" for everyone who had served in the colonial military to be granted British nationality.

"It was not the choice of those loyal people... to move to the People's Republic of China in June 1997 -- no self-determination for them, no referendum about their future," he said in a House of Commons adjournment debate on March 11. Adjournment debates are used to raise issues without requiring MPs to vote.

But Home Office minister James Brokenshire said in response that it was a "long-established practice" for British nationality to be lost when a country ceased to be part of Britain's territory.

He said that Hong Kong's "best-qualified key people" were given British nationality through a selection scheme.

Before the handover, 50,000 selected Hong Kongers -- mainly white-collar professionals and civil servants but also including military personnel -- were given British passports.

When contacted by AFP, the British Consulate in Hong Kong referred reporters back to Brokenshire's remarks. "This remains the position," a spokeswoman said.

The consulate did not confirm how many passports had been given out to military personnel before the handover, but Rosindell told parliament it was 500.

Neither did the consulate confirm how many were serving military personnel in 1997.

Those military personnel granted British passports were part of a 7,000-strong quota reserved for the "disciplined services" class, which also included police officers and firemen, the consulate said.

Before Britain gave the city back to China in 1997 it offered Hong Kongers a special "British National Overseas" (BNO) status to calm those worried about their future under Beijing's rule.

Holders can enter the UK without a visa and get consular assistance abroad, but have no right to live in Britain.

Around 400,000 of Hong Kong's 7.3 million residents hold the BNO passport and some are now calling on Britain to allow them residency as they seek to escape rising tensions.

- Trained to fight -

Various campaign groups in Hong Kong are pushing Britain for citizenship status, but the military veterans say their claims carry more weight.

"We were trained to fight. We also took an oath to pay allegiance to the Queen. We could have died for the country if there was a war," says former infantry corporal Fung Lit-kau, who applied for a British passport before the handover but was also unsuccessful.

Fung says he struggled to find a new career when he was forced to quit the military in 1997, 14 years into a 22-year contract, as the force was disbanded.

He finally became a postman in the United States after migrating there thanks to his sister-in-law being a resident, but regularly returns to Hong Kong and actively supports the campaign.

"They owe us an ethical responsibility. It's shameful for them to leave us behind," Fung, 55, said.

The history of Hong Kong-born ethnic Chinese people working for Britain's military can be traced back to the 19th century when they were hired to build military facilities and provide logistical support for British soldiers.

They were sent on overseas missions as well as defending the territory during the Second World War.

In 1962, the Hong Kong Military Service Corps was formed, making personnel recruited in Hong Kong regular soldiers of the British Army.

Tommy Poon, 74, who became a driving instructor after spending 22 years in The Royal Corps of Transport, said Hong Kong military personnel should not be treated differently to others.

"The Gurkhas also have it (British nationality) now. Why can we not?" Poon asked, referring to a celebrity-backed movement that won the right for British soldiers from Nepal to settle in the UK.

Another veteran, who preferred not to be named, expressed bitterness at their fate.

"We guarded against China along metal barricades on the border (before the handover). And now we are part of China... the situation is always going to be embarrassing for us," he said.