It is alleged that Zardad used a "human dog" as part of a merciless campaign of fear in his homeland between 1991 and 1996.

Zardad, who was later found in London and arrested, is being tried for plotting to take hostages and torture them in Afghanistan in a landmark case.

Zardad, 41, of Gleneagles Road, Streatham, south London, denies conspiracy to torture and conspiracy to take hostages between December 31, 1991 and September 30, 1996.

The first witness, Abdul Ghafour, the son of an Afghanistan Ministry of Information and Culture official at the time, told the court he was stopped at a checkpoint by men with covered faces and sunglasses - "so you could not see what was behind" - and was taken to a container nearby.

Inside was a metal chair. "I was told to sit on the chair. They tied my hands at the back of the chair. They asked me repeated questions - where I was from and did I belong to a party. They started torturing me."

The judge, Mr Justice Treacy, asked Mr Ghafour to show him, counsel and then the jury his scars. Rolling up his trouser leg, Mr Ghafour pointed to his knee and showed his wrists to the court.

Cross examined by Zardad's counsel, Anthony Jennings QC, he denied that he had told a British police officer that he attended a 15 day training camp involving AK47s, rocket launchers, bombs, mortars and anti-aircraft guns.

The jury were told by the Attorney General, Lord Goldsmith, when he opened the case on Friday, that an international convention and English law allowed the trial in England of anyone who has allegedly committed torture or hostage-taking, irrespective of where those crimes were committed.