Imagine an urban counterinsurgency in a sectarian setting. It would probably be your bottom pick of conflict, as the Iraq adventure showed.

Now imagine an army on the ropes and devoid of actionable intelligence. The ancient Sun Tzu might have been the first to wed intel and victory, but his concept still rang true in Northern Ireland during the Troubles (1968-1998).

Yet it’s hard to obtain intel in a regular conflict, nevermind in a religiously divided battlefield where even your local allies may have a different agenda.

Hard, yes, but not impossible.

To gain information on the IRA, the British formed a unit with an operational flexibility that borderlined the illegal. The Military Reaction Force (MRF) did covert ops in civvies, double agents, front companies, torture, and even “legalized” killings.

This wasn’t your regular SOF unit.

The MRF was a comet: It passed and went with a blazing trail in just two years (1971-1973). During its brief life, its operators gained both respect and notoriety.

But it was too irregular, too flexible—indeed, too unmanageable. And after an operation went south, it was disbanded in 1973. The intelligence void its dissolution created was filled by the famous 14 Intelligence Company, a more professional and supervised unit.

The MRF’s goal was two-fold: first, sow confusion, and thus division, within the IRA (the Official IRA and the Provisional IRA) with covert attacks; and second, gain intel through double agents, front companies, and undercover surveillance.

With less than 40 men in its ranks, it was divided into squads each led by SAS or SBS former operators; a handful of women may have served in the unit, but it’s uncertain (the 14 Intel Co. did allow female operators).

The MRF certainly didn’t have a passive mindset.

Their arsenal contained every weapon imaginable; favorite IRA weapons such as the M-16 and AK-47 were preferred since the MRF aimed at unaccountability. In a 2013 BBC interview, former operators claimed shoot-to-kill authority—whether armed or unarmed, they apparently didn’t fuss.

“If they needed shooting, they’d be shot,” one said with remarkable ease. “Rules of Engagement, what’s that?”

The unit’s surveillance operations are equally interesting.

In 1971, the MRF began its covert surveillance program. Dressed in civvies and driving ordinary cars, its operators combed Belfast’s neighborhoods for information and targets. In their task, the could rely on double agents. But it’s the MRF’s front companies that produced the most information.

Its operators set two such schemes: The Four Square Laundry, a mobile laundry service, and the Gemini Health Studios, a massage parlor.

Four Square Laundry serviced known IRA houses. They studied the laundry. Literally. If the number of clothes and linen brought were inconsistent with the houses’ occupants, the British knew that something wasn’t right.

In the Gemini Health Studios, operators would massage information from unsuspecting IRA members or sympathizers. But the front companies didn’t last long. In 1972, the IRA found out about their existence from a couple of double agents. On 2 October 1972, an attack of the two schemes left one British soldier dead, numerous wounded, and the unit’s future in peril. A review of the MRF took place, and the unit was disbanded shortly thereafter.

Its operational records remain unaccounted for.