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TomSpencerIMG 1145In 1979, the Provisional Irish Republican Army (PIRA) ambushed a British Army convoy at Warrenpoint with two improvised explosive devices (IED), killing 18 servicemen. This represented the British Army's single greatest loss of life throughout its campaign in Northern Ireland (N.I) – the Troubles, writes Tom Spencer. A similar device was also used the same day to murder Lord Mountbatten (a member of the British Royal Family, former senior Royal Navy officer and Chief of the Defence Staff). This paper underlines how the attack required new tactics, techniques and procedures in order to achieve the element of surprise and lethal precision. A pioneering use of remote detonation and potent home-made explosives (HME) had profound security implications. This precipitated an impetus for continuous British electronic IED counter-measures, border securitisation and a shift in strategy. A co-ordinated intelligence regime manifested itself as a war prosecuted through the use of special forces and covert mechanisms in gathering intelligence. These precedents created UK legacy expertise with which to counter insurgency and terrorism.

Unprecedented paramilitary planning amplified the lethality of the Warrenpoint ambush. PIRA surveilled British army convoys that routinely travel via the A-2 road in situ. General Sir Mike Jackson, who attended the immediate aftermath of the ambush, attested that with few routes available, occasional use of this road was required to avoid setting a predictable pattern. The threat of IEDs, situated to anticipate security forces, already exercised the minds of British command; targeted bombings set no new precedent. Notably, in 1976 PIRA led a failed IED attack against a Royal Marine patrol travelling on the A-2. Having spotted an IED command wire, the patrol withdrew to cover beside Narrow Water Castle Keep. PIRA however scrutinised this drill, predicting the success of an initial bomb would almost certainly lead the British to establish an Incident Command Post (ICP) within the 'cover' of Stone Lodge Gateway.
Returning in 1979, PIRA surreptitiously concealed two sophisticated devices, remotely priming the second after the first deadly blast to schedule detonation 'on target'. The timed strike of this larger secondary device, some 30 minutes later, predicted the precise arrival of a Quick Reaction Force (QRF) helicopter squad. The bombings killed 18 soldiers, the single greatest loss of British personnel during the Troubles. Meticulous planning thus exploited a forecast of vulnerabilities to fix and strike British forces in time, and space with unparalleled 'success'. Orchestrated through intelligence failures, Warrenpoint was a new threat from pattern analysis.

The technology behind this intelligence coup, found within the two IEDs, had a previously unseen level of sophistication. Exercising drills in situational awareness, the Royal Marine patrol that had identified the roadside bomb in 1976 had done so by its command wire, and thus thwarted PIRA's attack. Compromised by technology, PIRA pioneered the use of remote controlled devices, repurposing radio-controlled units from model aeroplanes in the early 70s to ensure its bombs remained concealed. However, by the mid-70s British security forces realised this, jamming the transmitter frequencies of such commercial units to prevent, or prematurely initiate, IEDs. By 1979, PIRA's response was to incorporate encoding/decoding devices to ensure its devices were impervious to 'stray signals'. British counter-measures and terrorist innovations thus became a cycle of 'cat-and-mouse' across the radio spectrum.

The operational worth of accumulative insights, not least coded electronic switches, was demonstrated in the Warrenpoint ambush. With remote devices, PIRA operators were able to strike the moving British convoy from a concealed vantage point, across River Newry, from within the jurisdiction of the Irish Republic. Anticipating countermeasures, its second device was primed by covert radio receiver-decoder apparatus; and guaranteed to detonate 'on target' via a repurposed Swiss Memopark Timer, for secure mechanical wind-down. PIRA's innovations thwarted British counter-measures; exercised lethal precision; exploited geographic, and political distances; and thereby presented an unprecedented threat. This reignited a protracted arms race that necessitated new and progressive British counter measures, requiring localised considerations and cross-border co-operation with the Republic of Ireland.

A new imperative for rural security scrutiny and border co-operation was further pressed by latent bomb-making infrastructure. The scale of destruction at Warrenpoint came about through homemade explosive (HME). PIRA combined agriculture fertiliser - ammonium nitrate (AN), diesel fuel oil (FO) and the economical use of stolen dynamite to create a HME 'ANFO'. Although in wide use by the mid 1970s, the amount used in the ambush, around 700kg, was on an unseen industrial scale.

Access to, and the refinement of, the vast amounts of this agri-chemical required in bomb manufacture pointed to the rural South of County Armagh, and the neighbouring Republic of Ireland. Beyond technical ingenuity, manufacturing HME on this industrial scale required a safe haven from where the logistics of sourcing and processing readily available farm fertiliser could remain concealed. Undetected, the delivery of an IED laden 'hay trailer' to Warrenpoint was testimony to this.

Under the cover of farming real estate, PIRA's network amassed new capabilities to the extent its South Armagh 'brigade' became instrumental in preparing vehicle-born IEDs (VBIED). The network later enhanced 'ANFO' HME with Nitrobenzene and Semtex boosters, and sustained the supply of VBIEDs for a further two decades of terrorism. Warrenpoint ambush was therefore a prelude to a long campaign underpinned by strategic infrastructure. Denying PIRA the use of its most lethal arm became a challenge of new dimensions.

Security implications.
This threat precipitated British government policies and practices, not least to mitigate the frictions that rose post ambush between the Northern Ireland's Royal Ulster Constabulary (RUC) and the British Army. RUC Chief Constable Sir Kenneth Newman maintained the Army's mid-70s shift to helicopter resupply of its South Armagh garrisons afforded PIRA's instrumental freedom of movement'. Lt-Gen Sir Timothy Creasey, General Officer Commanding Northern Ireland, argued for 'British Army exclusivity in liaison with the Republic of Ireland's police force'.

This was met by a government initiative to foster Army-RUC co-ordination to prosecute a new intelligence-led security strategy. Maurice Oldfield, former head of MI6, was appointed Security Co-ordinator in Northern Ireland to deliver inter-agency intelligence co-operation. Although contentious, covert surveillance was placed at the heart of counterterrorism. Observation towers were established in South Armagh to combat rural safe haven and porous borders. By 1982, a British network of informers and agent handlers, the Force Research Unit, was also established.

It helped compromise PIRA operations, infiltrating PIRA's own internal security unit. By 1988, the new "All-source Intelligence Cell" enhanced intelligence sharing between the FRU, RUC, Special Branch and MI5. This partnered with British Special Forces that had been ramped up to eradicate PIRA in the countryside. Although prior agreed, the Westminster policy of RUC "police primacy" and expansion now saw British army 'draw down' coincide with increased covert forces.

The Warrenpoint Ambush established a series of precedents that acted as a catalyst for a new British strategy in Northern Ireland:

Characterised as an intelligence-led ambush, PIRA exercised quasi-pattern analysis to realise a new threat against security forces. It progressively pooled the use of new TTPs to achieve a kinetic strike of substantial efficacy. It involved the assimilation of commercial technologies in order to achieve the element of surprise and 'military' precision. Whilst terrorist developments in the use of technology were long-standing, PIRA successfully circumvented electronic IED-counter measures at Warrenpoint. The use of encoded radio and remote detonation set in motion a protracted cycle of 'cat-and-mouse', with a renewed British imperative for electronic countermeasures continuing until the 1990s.

Far reaching security implications were born out this technological ingenuity. PIRA had planned, prepared and orchestrated its attack from across the Irish border. The spectre of a rural bombing-making network that produced potent HME on an industrial scale, placed a new premium on securing N.I's rural frontiers. Denying PIRA safe sanctuary and freedom of movement became a new imperative for the British. Northern security was also now dependent on the involvement of the Irish Republic.

British security strategy predicated a pre-existing policy of Northern Irish "police primacy" with army draw down, yet it now had to deploy special forces supplied with intelligence drawn from a new surveillance regime comprised in diverse 'infrastructure'. A covert, intelligence-led strategy was thus placed at the heart of counterterrorism. This saw British policy drive intelligence-sharing between all stakeholders to successfully prosecute its war on PIRA. Reviewing the hard-earned lessons of 'the Troubles' will further this campaign's military legacy.

Key points summary:

- PIRA's transition to an insurgency was born of paramilitary 'necessity'; Op MOTORMAN denied it urban safe havens and freedom of movement (July 1972);
- PIRA decentralised command via localised Active Service Units (ASUs);
- South Armagh Brigade's long standing 'ruralised' ORBAT was a model for localised, cell-based insurgent ops
- PIRA learned from its failures so it was able to execute the Warrenpoint ambush
- COIN necessitated localised and cross-border security co-operation
- The devolution of policing post ambush continued under the ongoing narrative of Northern Ireland "police primacy" ('Ulsterisation');
- British security preconditions affected true N.I police autonomy
- Post Warrenpoint, co-operation between the UK and the Republic of Ireland led to a role for the Eire government in Northern Ireland within the Anglo-Irish agreement.
- The conflict was a political problem; it required a political solution.


- A.R. Oppenheimer, (2018), 'Hitting the Forces: Warrenpoint and Newry', in: IRA, Bombs, Bullets: A History of Deadly Ingenuity, 1st ed, Irish Academic Press, 1st ed, chp 5-6.

- A. Mumford, (2012), 'The Counter-insurgency Myth': The British Experience of Irregular Warfare, Routledge, 1st ed.

- B.A. Jackson et al, (2005), 'the Provisional IRA', in: Aptitude for Destruction, vol 2, RAND corporation, chp 5.

- B. Whaley, (2016), 'Case 22: The Warrenpoint Double-Ambush, Northern Ireland 1979', in: Practice to Deceive, learning curves in Military Deception plans, ed. S.S Aykroyal, U.S Naval Institute, Naval Institute Press, 1st ed, pg 56-57.

- C. Kennedy-Pipe, (1997), 'The origins of the present Troubles in Northern Ireland', Routledge, 2nd ed.

- Capt. N.J. Eckert et al, (1994), 'Death at Narrow Water: The Anatomy of Ambush', in: Military Intelligence Professional Bulletin, PB 34-94-4, OCT – DEC, pg 28-30.

- Chief of the General Staff (CGS), General Sir M. Jackson, (2006), 'Operation Banner': An analysis of military operations in Northern Ireland, Army code 71842, Ministry of Defence, 06 JUL.

- G. Gillespie, (2009), 'The A to Z of the Northern Ireland Conflict', Scarecrow Press, Incorporated.

- General Sir M. Jackson, (2007), 'General Sir Mike Jackson relives IRA Paras Bombs', The Telegraph, 05 SEPT.

- J. Moran, (2016), 'From Northern Ireland to Afghanistan': British military intelligence operations, Ethics and Human Rights, Routledge, 2nd ed.
- M. Ingram, (2012), 'Stakeknife': Britain's Secret Agents in Ireland, ed. G. Harkin and I. Hurst, O'Brien Press, 1st ed.

- P, Gill, (2017), 'Tactical Innovation in the PIRA', in: How terrorists learn: adaptation and innovation in political violence, Studies in Conflict and Terrorism journal, vol 40 (7).

- Sir D.B. Omand, Principal Private Secretary to the Defence Secretary, (1979), 'a letter to the CGS', WARRENPOINT EXPLOSION 28 AUG 1979 - DEAD and MISSING BELIEVE KILLED, Ministry of Defence, Whitehall, 28 AUG.

- S. Darcy, (2019), 'To serve the Enemy': Informers, collaborators, and the Laws of Armed Conflict, Oxford University Press, 1st ed.

- The Anglo-Irish Agreement, (1985), Agreement between the Government of Ireland and the Government of the United Kingdom. Available at:

- T.Geraghty, (2000), 'The Irish War': The hidden Conflict between the IRA and British Intelligence, Johns Hopkins University Press, 1st ed.

- The Rt. Hon. Sir D. de Silva QC, (2012), the Report of the Patrick Finucane Review, the House of Commons, Crown Copyright, Vol 1, 12 DEC.

- The Sunningdale Agreement, (1973), Tripartite agreement on the Council of Ireland
- the communique issued following the Sunningdale Conference. Available at:

Thomas Spencer M Sc is a Research Associate with the U.K. Defence Forum

First published May 2020 at Defence Viewpoints

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