The trial of an Afghan man charged with conspiring to kidnap and torture in his homeland has begun in London.
Mr Zardad's trial was opened by Attorney General Lord Goldsmith
Faryadi Sarwar Zardad denies charges relating to a period from 1991-96, while he was an alleged warlord.
The case is the first of its kind to be tried at the Old Bailey, said Attorney General Lord Goldsmith, prosecuting.
Mr Zardad's defence counsel urged jurors to keep an open mind about the allegations and consider whether witnesses might have "an axe to grind".
Section 134 of the Criminal Justice Act allows Britain to try alleged torturers regardless of where the crime is alleged to have occurred.
It was adopted in 1988 in line with the United Nations Convention Against Torture.
Although the matters did not concern the UK, Lord Goldsmith said some crimes are so heinous they can be tried in any country.
He told the court Mr Zardad, 41, was a war lord in charge of the Sarobi area outside the Afghan capital Kabul, at a time of much internal fighting.
"He wanted a fearsome reputation of being cruel and merciless at his military checkpoints, so that people passing through would obey them absolutely and give
them money and goods," he said.
He also stopped supplies getting through to a rival party in Kabul.
The court heard the defendant and his soldiers used "indiscriminate and unwarranted violence".
"They would beat, wound and even shoot and kill civilians. They would detain and imprison them and hold them for ransom," he said.
He told the jury a "human dog" was kept in a hole and set on passers-by to bite and attack them.
"In pursuing that course of conduct it was inevitable that they would commit the crimes of torture and hostage taking," he said.
Lord Goldsmith said one witness would give evidence he was beaten three times at a checkpoint in Sarobi.
"He saw Zardad on two occasions with a large number of bodyguards at the main checkpoint in Sarobi," the Attorney General said.
"Zardad must have known and consented to the infliction of severe pain and suffering on this witness."
Another would tell how he was abducted, tortured and witnessed the deaths of 24 fellow prisoners during a five-month detention, he said.
But defence counsel Anthony Jenning, told the jurors not to be prejudiced by the nature of the allegations against Mr Zardad.
The Afghan had fought both the Russians and the Taleban in his homeland, he said, at which time many regarded him as a peasant freedom fighter.
Mr Jennings said Mr Zardad's power between 1992 and 1996 had made him a "hate figure" to opponents and may have inspired propaganda against him.
"No-one doubts there were atrocities committed by warring factions," he said.
"But Mr Zardad is not here to bear some general responsibility for that. He is here to stand trial for specific allegations."
Explaining the charges, Lord Goldsmith said torture was committed if a public official or person acting in an official capacity intentionally inflicted suffering on another in performance or purported performance of official duties.
He said Mr Zardad had admitted acting in an official capacity in the region while a commander in the Hezb-i Islami - the Islamic Party.
And he had admitted his command was based outside Sarobi on the Kabul side.
It was for the jury to decide on the evidence whether Zardad was implicated in the incidents alleged, he said.
The jury will hear from witnesses in Afghanistan via a video link and be shown video footage.
Zardad Sarwar, 42, of Gleneagle Road, Streatham, south London, listened to the case against him through an interpreter in the dock.
Mr Sarwar - also known as Zardad Khan - moved to Britain in 1998 and was running a pizza restaurant in south London when he was arrested in July 2003.