A British sniper gunned down a jihadi from almost 1.5miles away in what is reportedly the best long-range shot ever in the SAS.

The sergeant killed the Islamic State commander with a .50 Calibre machine gun, shooting him in the chest. This feat is believed to be the first time the machine gun has been used for a sniper hit by the SAS.

The Islamist's arm and shoulder were torn off due to the force of the bullet and he died instantly. The jihadi was on a British and US kill list.

A veteran of Iraq and Syria, the sergeant was secretly patrolling a region of northern Afghanistan under Islamic State control, The Daily Star Sunday reports.

An SAS sniper mounted a machine gun that is nearly 40 years old on top of a military vehicle and attached a special sight to kill the commander (file photo)

His gun is being decommissioned and displayed in the elite unit's Hereford headquarters.

The .50 Cal Browning - which is almost 40 years old - was mounted on an Army vehicle.

The Islamic State commander was killed while addressing his men when the sergeant shot him in northern Afghanistan (pictured, an Islamic State fighter in Raqqa, Syria)

A senior officer stationed at the Joint Special Operations Command HQ in Kabul gave the go-ahead for the kill.

One source told the paper a special sight was fitted on the machine gun and a spotter then estimated wind speed.

The sergeant killed the Islamic State commander with a .50 Calibre machine gun, similar to this model, shooting him in the chest

'He also took into account the heat of the day and the light,' they said. 'The image of his target was quite "watery" because of the heat being given off from the ground.

'The Islamic State fighter seemed to be briefing his men as he stood addressing fighters for about 20 minutes.

'It took several seconds for the round to hit the commander who appeared to fly into several pieces. For a few seconds no-one moved. When they realised what had happened they got up and ran away.'

The paper reports that the kill is thought to have saved more than 20 lives. The gun was used as a long-range weapon in the 1950s during the Korean War.