An illegal immigrant tied up, tortured and robbed his former boss and her children to pay off the Triad gangsters who smuggled him into the country.

Chinese Xiang Lin, 39, one of three masked men who broke into the plush four-bedroom home, bound and gagged the single mother and her teenage son and daughter and then used a 50,000 volt stun gun to administer electric shocks on all three for an hour.

They made off with more than £8,000 in cash and jewellery from the property in Searles View, Horsham.

Lin was jailed yesterday for 12 years as Lewes Crown Court heard one of his accomplices had been murdered by the Triads while another had fled back to China.

The Triads - one of the world's biggest and most feared organised crime networks - brought the robbers illegally into the country around 2001.

Lin, who was not deported after his asylum application was rejected, worked for his victims at the Golden Dragon restaurant, Fitzalan Road, Horsham - one of string of businesses the family owned in Sussex - and knew the home would be "a soft target", the court heard.

However Lin, who has previous convictions for DVD piracy and drugs offences, was caught after a fingerprint left on the window he climbed through into the home was matched to a central database.

He was sentenced to 12 years in jail yesterday (TUESDAY) for his role in the robbery, carried out at 2.45am on May 18, 2007.

The two other members of the gang have never been caught. One is believed to have escaped to China while the other is thought to have been murdered by Triads for not repaying his debt.

Prosecutor John Price said: "The family were subjected to sadistic torture.

"At one stage the leader of the gang became angrier than ever with the mother and threatened the lives of her children if she did not say where more money was.

"He said: You had better come up with it now or your children will die.'"

The gang had broken into the home through a window and had woken up the family by punching them, thrusting guns into the faces or threatening them with screwdrivers.

Towards the end of the ordeal the gang grabbed a picture of the family.

Mr Price told the court: "They said they were taking the photo so that if they went to the police they would know how to identify then and would make arrangements to kill them."

The family, who have not been named but are of Chinese origin, have been left terrified by the robbery and have been forced to move home because of the ordeal, prosecutors said.

Detectives traced Lin to a rented property in Gravesend, Kent.

They arrested him on June 2 and charged him with robbery and possessing a fake handgun.

His former girlfriend Jing Ling, 24, also an illegal immigrant, was also charged with handling stolen goods.

Ling, who cried throughout the hearing, was sentenced to 12 months in jail.

The court heard she was given a silver necklace from the robbery and was aware it had taken place.

The pair, who both pleaded guilty, were living rough in a car shorty before the robbery before moving into the Gravesend home.

Defence lawyers said both feared for the lives on release from jail because of the "unpaid" Triad debts.

They said it was likely that Lin's family in particular would be targeted by the gangsters while he was in jail.

Judge Anthony Scott-Gall told Lin: "You subjected the victims to pain and terror and they are still suffering quite awful consequences 12 months later."

Judge Scott-Gall recommended both are deported upon completion of their sentences.

Author Martin Booth, whose book, The Dragon Syndicate, is an in-depth look at the spread of Triad culture, quoted a UN source as saying they constitute "the greatest potential criminal threat the world has ever known".

Booth traced the first "official" Triad group back to 9AD feudal China, when secret societies offered protection to families.

Gangs now have a foothold in countries as far apart as the Holland, Malaysia, Australia, the United States and South Africa. In the UK they are active in urban centres - mostly London, Manchester, Glasgow and Hull.

Recently there were an estimated 50 Triad gangs operating in Hong Kong. Britain is thought to be home to four major gangs, including the renowned 14K, which is arguably the biggest in numbers.

Their spread has been mirrored by a growth in the range of their criminal enterprise. They now profit on a mix of drug trafficking, extortion, prostitution, kidnapping, illegal immigration, counterfeiting, video piracy, loan sharking and gambling.

According to one estimate by Martin Booth, Triads are responsible for 90 per cent of the heroin trade.