A London taxi driver who made bombs to kill US soldiers in Iraq has been sentenced to a minimum of 38 years in prison.

Anis Abid Sardar, 38, became the first person to be convicted in a British court for taking part in the Iraqi insurgency when a jury found him guilty of murder and conspiracy to murder on Thursday.

One of the improvised explosive devices (IEDs) caused the death of Sgt First Class Randy Johnson, 34, of 2nd Stryker cavalry regiment, when it blew a hole in the bottom of the armoured vehicle he was travelling in on 27 September 2007.

Mr Justice Globe sentenced Sardar, from Wembley, north-west London, to life imprisonment on Friday at Woolwich crown court, south-east London.

Globe told him: “Sgt First Class Johnson’s loss was one of the sad tragedies in what was going on in Iraq in 2007.

“By the jury’s verdict it is a loss for which you are directly responsible.”

He said that Sardar, who claimed that he had been involved just once in bomb-making to protect the Sunni community from Shia militias, “had a mindset that made Americans every bit the enemy as Shia militias. Both were in your contemplation at all times”.

Sardar was linked to three other IEDs, two of which were recovered intact. The third was safely detonated by a bomb disposal team. However, two US soldiers from 2nd battalion, 5th cavalry regiment, were seriously injured when a sniper shot them as they guarded the latter device on 20 March 2007.

Sardar was arrested seven years later when officials at the FBI’s terrorist explosive device analytical centre found his fingerprints on some of the bombs.

Prosecutor Max Hill QC read a short message from Johnson’s widow, Claudia, in which she said: “Thank you so much, it’s a big relief to know that justice has been served. However, it does not change much for us. Randy will be greatly missed.”

The prints were taken when he was randomly stopped at Heathrow as he returned to the UK from Syria two months after the soldier’s death.

Sardar’s fingerprints were not on the device that killed Johnson but all four bombs bore those of his co-conspirator, Sajjad Adnan. Prosecutors said the pair had worked together and with others to build and plant the IEDs. Adnan, who is not British, was arrested after the bombings and handed over to the Iraqi authorities. His whereabouts are unknown.