A warning, General Sir Mike Jackson's interview may be upsetting for some.
A former head of the British Army says it was "mayhem" when he arrived at Narrow Water, following attacks which killed 18 soldiers.
The IRA attacks on 27 August 1979 near Warrenpoint resulted in the highest death toll suffered by the British Army on a single day in Northern Ireland.
Hundreds of veterans have gathered to remember personnel killed by the IRA bombs 40 years ago.
Former Chief of the General Staff, General Sir Mike Jackson, was a company commander in the wake of the deadly ambush.
He was at Bessbrook British Army base when he was ordered to the site of the attack to set up a security cordon.
General Jackson said that there was a "traumatic" scene of devastation when he arrived at Narrow Water.
"Burning vehicles, dead bodies, bits of bodies.
The IRA exploded the remote-control bombs from a firing point on the other side of the river, in the Republic of Ireland.
Six soldiers travelling in an Army vehicle were killed by the first bomb and as colleagues arrived to help, a second device detonated, killing 12 more troops.
"One's got to admit it was a clever plan and they succeeded," Gen Jackson said.
General Sir Mike Jackson served for 45 years and completed three tours of Northern Ireland during the Troubles.
"The Northern Irish problem is a political problem at its root," he said.
"It therefore must have a political settlement. Which indeed, is represented by the Good Friday agreement.
"This was not a conventional war, this was a campaign by the opposition, the IRA, designed to force the British government to concede a united Ireland.
"But the British government weren't going to do that... Even when the IRA struck at the heart of the British political establishment, which they did.
"You had a form of almost stalemate.
"A strange sort of war of attrition where the IRA were able to impose casualties on the army and the police. But equally, they were not going to get any major concessions.
"I look at it as the job of the security services was to keep the space open for that political settlement to emerge.
"For the IRA to realise violence wasn't going to get them their wish, and that there would have to be a more political approach to the future of Northern Ireland.
"And thank heavens that settlement did emerge with the Good Friday agreement."