A SCOTTISH battlefield has yielded a remarkable discovery more than three centuries after the slaughter ended.
Archaeologists have found proof of the first ever use on British soil of a terrifying new weapon at the Battle of Killiecrankie, at which 2,500 Jacobites annihilated a force of 4,000 redcoats.
A three-inch fragment of corroded iron is all that remains of a hand grenade thrown by government soldiers at the Jacobite ranks during the 1689 engagement near Pitlochry.
As well as being the first documented use in combat of the hand grenade anywhere in Britain, there is also evidence it may have been at the centre of an early ‘friendly fire’ episode.
Experts say the position of the fragment strongly suggests the grenade rolled back towards the English soldiers and exploded among them, causing death and mayhem and even contributing to the scale of their defeat.
It was previously thought that the hand grenade was first used at the 1719 Battle of Glenshiel, near Inverness, when the Jacobites were defeated.
But work by Glasgow University archaeologists Dr Tony Pollard and Neil Oliver for the BBC2 television series Two Men in a Trench proves the weapon was used at least 30 years earlier.
Early grenades were like cartoon bombs: an iron sphere packed with gunpowder and a fuse sticking out of the top. Grenadier troops were formed in 1677 as the 17th century version of the SAS. Although grenadiers fought at the 1685 Battle of Sedgemoor, no grenade fragments have ever been found.
Pollard said: "We have discovered [at Killiecrankie] the first occasion that a hand grenade as we know it was thrown on British soil. We knew that Grenadiers were there, but not that they used their grenades for the first time."
The Battle of Killiecrankie was one of the bloodiest battles of its era. Around 2,500 sword-wielding Jacobites under John Graham of Claverhouse - Bonnie Dundee - slaughtered more than 4,000 redcoats under General Hugh MacKay, leaving only 400 alive.
MacKay’s diary of the battle recorded that his redcoats were able to fire only two rounds from their muskets before being overwhelmed by the charging Highlanders.
According to Pollard, the position of the grenade provides evidence that after being thrown uphill, it may have rolled back towards the English troops and helped the Jacobites achieve their unlikely victory.
He added: "We know that the government forces were situated on a ridge downhill from the Jacobites, who had the better position, so it could have rolled back and killed government troops.
"The grenade may also have gone off prematurely as fuses were temperamental and several grenadiers in that era lost hands because of this."
Pollard said that the excavation had also finally solved the question of the battle’s exact location. He added: "Many history books have the government troops lined up in entirely the wrong place. The A9 now runs through the middle of it, but what we found there was amazing. We were picking up musketballs in lines, where they had landed after a volley. We could tell from the distortion that a lot of them had passed through human bodies.
"The Jacobites were outnumbered, but a classic Highland charge down the pass wiped out the government column and only a few were lucky enough to escape."
• The new series of Two Men in a Trench starts on BBC2 this Thursday at 7pm.