The house in Mitcham, Surrey, where Commander Zardad lives

He operated roadblocks at a town called Sarobi, on one of the major routes into the Afghanistan capital of Kabul, during the early 1990s.

He is accused of using his position to stop every vehicle that passed at gunpoint and carrying out extortion, robbery and murder.

When questioned by Newsnight he denied doing anything wrong.

"We never harassed anyone, and we never killed anyone," he said.

"I was not the commander at Sarobi. I was a commander at Kabul. I was just an advisor at Sarobi."

When the Taleban took over, Commander Zardad had enough money to escape to Britain.

"I come here to England because we have lots of trouble because the Taleban are trying to kill me and make trouble," Commander Zardad said.

Human dog

"I am not doing anything in England, I am just living my life."

Commander Zardad was typical of the anarchic rule that ravaged Afghanistan after the withdrawal of Soviet forces in 1989.

But former Agence France Presse reporter Stefan Smith told the BBC Commander Zardad stood apart because of his power.

"What really brought him apart from others is the amount of terror he reaped," he said.

He recalled one instance when he said he saw Commander Zardad's men kill 10 unarmed men on board a bus.

Underground cave where "human dog" was kept

He was used to attack people who were unwillingly to cooperate with Commander Zardad - biting them and even killing them - according to eyewitness reports.

The BBC was tipped-off about Commander Zardad's whereabouts by Afghanistan's hardline ruling Taleban militia, who ousted him from his Sarobi base in 1996.

Ann Clwyd MP who chairs the parliamentary human rights group, said if the evidence the BBC had was correct, it was very worrying.

She said she was concerned that there were no procedures for checking the identity of suspected war criminals.

She said if the political will was there it should be possible to bring suspected torturers to justice.

"There is a lot more public interest in seeing the people accused of war crimes are brought to justice," she said.