The Provisional Irish Republican Army (IRA) attacks a British Army permanent vehicle checkpoint complex manned by the King’s Own Scottish Borderers (KOSB) near the Northern Ireland–Republic of Ireland border at Derryard, north of Rosslea, County Fermanagh, on December 13, 1989.

According to journalist Ed Moloney, the IRA Army Council, suspecting a great deal of infiltration by double agents at the grassroots level of the IRA, decide to form an experimental flying column (rather than the usual active service unit) to mount a large-scale operation against a permanent vehicle checkpoint along the border. It hopes that this will prevent any information leak that might result in another fiasco like the Loughgall Ambush of 1987.

Moloney maintains that the planning is in the charge of Thomas Murphy, alleged leader of the South Armagh Brigade, and that the raid is to be led by East Tyrone Brigade member Michael “Pete” Ryan. Journalist Ian Bruce instead claims that the IRA unit is led by an Irish citizen who had served in the Parachute Regiment, citing intelligence sources. The column is made up of about 20 experienced IRA volunteers from throughout Northern Ireland, eleven of whom are to carry out the attack itself. Bruce reports that IRA members from County Monaghan, supported by local Fermanagh militants, carry out the raid.

The target is a permanent vehicle checkpoint at Derryard. Described as a “mini base,” it includes an accommodation block and defensive sangars. It is manned by eight soldiers of the 1st Battalion, King’s Own Scottish Borderers and a Royal Ulster Constabulary (RUC) officer. The eleven IRA members are driven to the checkpoint in the back of a makeshift Bedford armoured dumper truck. They are armed with 7.62mm AK-47s, 5.56mm ArmaLite AR-18s, two 12.7mm DShK heavy machine-guns, RPG-7s, different kinds of grenades, and a LPO-50 flamethrower. The heavy machine guns and the flamethrower are mounted on a tripod on the lorry bed. To assure widespread destruction, the column plan to detonate a van bomb after the initial assault.

The attack takes place shortly after 4:00 PM. IRA members seal off roads leading to the checkpoint in an attempt to prevent civilians from getting caught up in the attack. The truck is driven from the border and halted at the checkpoint. As Private James Houston begins to check the back of the truck, the IRA open fire with assault rifles and throw grenades into the compound. Two RPG-7s are fired at the observation sangar while the flamethrower stream is directed at the command sangar. Heavy shooting continues as the truck reverses and smashes through the gates of the compound. At least three IRA volunteers dismount inside the checkpoint and spray the portacabins with gunfire and the flamethrower’s fire stream, while throwing grenades and nail bombs. The defenders are forced to seek shelter in sangars, from where they fire into their own base. A farmer some distance away sees an orange ball of flames and hears gunfire ‘raking the fields.’ As the truck drives out of the now wrecked compound, a red transit van loaded with a 400-lb. (182 kg) bomb is driven inside and set to detonate once the IRA unit has made its escape. However, only the booster charge explodes.

The attack is finally repulsed by a four-men Borderers section from the checkpoint that is patrolling nearby, with the support of a Westland Wessex helicopter. The patrol fires more than 100 rounds at the IRA unit. The Wessex receives gunfire and is forced to take evasive action. The IRA column, at risk of being surrounded, flee toward the border in the armoured truck. It is found abandoned at the border with a 460-lb. (210 kg) bomb on board.

Two soldiers are killed in the attack: Private James Houston (22) from England and Lance-Corporal Michael Patterson (21) from Scotland. Corporal Whitelaw is badly wounded by shrapnel and later airlifted for treatment. Another soldier suffers minor injuries.

There is outrage in Westminster and among unionists, as a supposedly well-defended border post has been overrun by the IRA and two soldiers killed. On the other hand, according to Moloney, there is also some disappointment among republicans. Despite the positive propaganda effect, the quick and strong reaction from the outpost’s defenders convince some high-ranking IRA members that the Army Council has been infiltrated by a mole.

KOSB officers and security sources believe that the IRA unit involved was not locally recruited, putting the blame instead on IRA members from Clogher, County Tyrone and South Monaghan in the Republic. The same sources say that the attack was executed “in true backside-or-bust Para style.”

After the action of Derryard, the British Army in Northern ireland are issued the French designed Luchaire 40mm rifle grenade, fitted on the muzzle of the SA80 rifle. This gives the troops a lightweight armour piercing capability to deal with the threat imposed by improvised armoured vehicles. Permanent checkpoints along the border are also fitted with general-purpose machine guns. From 1990 until the end of the IRA campaign in 1997, there are a number of further bloodless, small-scale attacks against permanent vehicle checkpoints along this part of the border using automatic weapons, particularly in County Fermanagh and against a military outpost at Aughnacloy, County Tyrone.

Two soldiers, Corporal Robert Duncan and Lance Corporal Ian Harvey, are bestowed the Distinguished Conduct Medal (DCM), while Lance-Corporal Patterson receives a posthumous mention in dispatches for his actions during the attack. The checkpoint is dismantled in March 1991, as part of a major border security re-arrangement codenamed Operation Mutilate.

(Pictured: Republican memorial at Carragunt bridge, on the border between Northern Ireland and the Republic, often crossed by Provisional IRA forces during the Troubles to attack British targets inside County Fermanagh)