GOLF 40, a British Army observation tower on top of Crotlieve Mountain near Forkhill, is jokingly referred to as the Slab Murphy Memorial Watchtower. Long after the Troubles ended, it was kept open precisely with last Thursday’s series of raids on Murphy’s property a couple of miles away in mind.

Last year Golf 20 and Golf 30, its two companions, were decommissioned in a blaze of publicity. Both were closer than G40 to Murphy’s farm and smuggling complex in Ballybinaby, but it was G40, on elevated ground two miles away, that commanded the best view. So effective was its imaging equipment that car numbers going into the complex from either side of the border could be read.

During the IRA campaign Murphy, the organisation’s chief of staff, had studied carefully the areas of “dead ground” invisible from the three towers. He built a concrete wall and sheds to protect his smuggling empire, to facilitate the movement of explosives and to minimise the opportunities for surveillance.

At first light on Thursday, soldiers, who live in an underground chamber deep in the mountain, had an excellent view of Ballybinaby from G40. What they missed was picked up by a British Army Lynx helicopter hovering nearby. Under their watchful eyes, a huge security operation swung into place from 6am. It will probably be the last significant operation that G40 sees before it is demolished later this year.

From Newry and Armagh on the northern side of the border, more than 100 troops and a similar number of police and customs officers converged on Murphy’s estate. The 50- vehicle convoy paused at No 45 Larkin’s Road to search a derelict building and to establish a road block. “We want to seal off the area as a crime scene,” a police source said.

Soldiers fanned out into the fields to secure the area, while on the southern side of the border a smaller convoy of 30 vehicles with gardai, customs, army and Criminal Assets Bureau (CAB) personnel swung into action, establishing its roadblock at Ballybinaby’s crossroads, just a short distance from the British operation. There were unmarked detectives’ cars and marked garda cars, Emergency Response Unit 4x4s, technical bureau staff in crime-scene vehicles and vans for taking away seizures.

The search used great sensitivity to the political boundary running through the farm. Members of the garda mapping division were present and a PSNI source said: “A lot of planning went into it. This was a joint operation so that we would both be able to search in our own jurisdiction. Any mistakes would have legal resonance.”

They searched all day but could not find “Slab” Murphy, who is believed to have slipped the cordon. Garda sources say his half-eaten fried breakfast was still on the table when they arrived, suggesting he had fled after getting a few minutes’ notice of their arrival.

The security forces on both sides of the border must now sift through a vast haul of documents, computers and disks that they recovered. Evidence will be compared with information seized by the CAB in the south and the Assets Recovery Agency in Manchester during raids last year in relation to a property portfolio linked to Francis Murphy, Slab’s brother. Up to 12 vehicles, about 30,000 cigarettes, a large quantity of fuel suspected of being illegally laundered and approximately €450,000 of cash in euro and sterling were seized, as well as £414,000 (€600,000) in cheques found in plastic bags in the hay shed.

There were also two shotguns and chemicals that could be used for laundering diesel.

The finds looked impressive as garda and PSNI officers drove them away that evening, but Murphy’s absence gave some cause for concern. Gardai and CAB believe the IRA commander may have hid himself, presumably in his night clothes, in a bunker. Another possibility is that after being warned by lookouts of approaching vehicles, he sat out the raid in the home of Michael Conlon, his friend and neighbour. Conlon’s house was not included in the search operation and consequently could not be entered.

Some sources in Irish customs suggest that the IRA leader had been tipped off well in advance and was able to remove the most incriminating material. They point to a break-in at Dundalk courthouse, where documents relating to the raids were held, on Wednesday evening. “I’m surprised Slab didn’t leave out a cake for us,” one officer said.

However, gardai have discounted any link between the Dundalk break-in and the raid. Their main concern on Thursday was seizing evidence. Arresting Murphy was not an objective, although he would have been lifted if he was there. On past form, gardai expect him to present himself in Dundalk station in the next few days.

Times Recommends

• Should Knox’s trial even have reached the courtroom?
• 'Was it real?' The US bailout nightmare
• Iranian opposition plays the long game