Who protects Irish skies? The secret air defence deal that dates back to the Cold War

Ireland’s air defence agreement with the UK dates to the early days of the Cold War and remains in place today despite legal concerns

Late last year Ian Paisley Junior, MP for North Antrim, asked the London government about its air defence arrangements with Ireland, particularly in regard to intercepting “Russian reconnaissance bombers” off Northern Ireland and Donegal.

He referred to two incidents in 2020 where Russian Tupolev TU-95 “Bear” aircraft twice entered Irish-controlled air space before being escorted away by RAF jets, a type of provocation which had become more and more common in recent years.

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The reply from James Heappey, a minister of state for defence, was short but unusually candid. He told Paisley “RAF jets have deployed into Irish airspace on occasion. It is for the Irish Government to set out their policy on why, when and how.”

For officials in Dublin it was perhaps too candid. For years official policy in Dublin has been to refuse to publicly discuss Ireland’s air defence arrangements with the UK or the presence of RAF interceptors in Irish airspace. However, according to interviews with political, diplomatic and military figures, such an agreement goes back over 70 years to the early days of the Cold War and has been updated and amended several times over the decades with the approval of Cabinet.


One side effect of that agreement is that the Irish government never thought it necessary to invest in its own credible air defence system even after military officers raised serious legal concerns about its arrangement with Britain.

Today, in the face of an increasingly belligerent Russia, Irish air defence capabilities are at their lowest point in decades. Furthermore, depending on the results of a High Court action, the Government may finally be forced to reveal the extent it relies on the UK in this area.

The first air defence agreement between Ireland and the UK was drawn up in the early 1950s, when tensions between east and west were near boiling point and the Soviet Union was developing nuclear-armed bombers capable of reaching western Europe and beyond.

The Irish State, though neutral, had made it clear it would be on the side of the west in any conflict. However, it was wholly unequipped to detect any Soviet airborne threat, never mind intercept it.

Whether or not Russia was interested in Ireland it was certainly interested in the waters around it, particularly what is known as the Greenland Iceland United Kingdom (GIUK) gap, a naval chokepoint which would be vital to control if hostilities broke out between the two superpowers. Ireland’s proximity to the gap meant both powers would be likely to disregard its sovereignty and neutrality if it offered any advantage in a war. For military planners the gap is just as important today.

With all of this in mind in 1952 Irish officials signed a formal agreement with London which would allow the RAF to transit Irish airspace if it detected a Soviet threat. It was essentially a formalised version of the unwritten agreement which allowed British aircraft to fly over the so-called Donegal Corridor to attack German ships and U-boats in the Atlantic during the second World War.

This agreement was brought before Cabinet on a semi-regular basis, where it was approved with little discussion. As the Cold War stayed cold the perceived threat retreated in the background and remained there for decades. Ireland’s neutrality and its geographic position on the west of Europe meant the threat of Russian bombers rarely kept politicians or civil servants up at night.

Of more concern were unauthorised incursions by British army helicopters into the Republic during the Troubles, usually as they pursued IRA suspects across the Border following an attack. To address this another secret agreement was arranged allowing British helicopters to travel up to 5km into the Republic for the purposes of pursing subversives, inspecting suspect explosive devices and conducting photographic surveillance.

During this period the Air Corps did acquire jet aircraft which were used almost exclusively for training. But none were capable offering a credible air defence. Instead, having acquired its first helicopters in 1963, the Air Corps focused on civil operations including search and rescue and air ambulance missions.

Air defence became a matter of concern again in the wake of the terror attacks on the United States on September 11th, 2001. Along with the rest of the western world, Ireland woke up to the fact that commercial aircraft could potentially pose just as much of a threat as a hostile power.

The Defence Forces did possess Swedish-made RBS-70 air defence missile systems but, despite using advanced technology for the time, it was only suitable for point defence, such as big sporting events or State visits. Furthermore the system did not have the range to reach the operating altitude of commercial airliners. It also possessed radar-guided Bofors L/70 anti-air auto cannons, essentially an updated version of the type used by belligerents during the second World War. But these had even less range than the RBS-70.

Again officials took the view that the best defence was offered by the RAF. The secret British-Irish agreement was revised and updated to deal with potential terrorist threats. If a hijacked airline appeared over Irish airspace, for example after travelling across the Atlantic, the RAF would deploy jets from its Quick Reaction Alert squadron in Lossiemouth, Scotland which would be authorised to intercept and if required shoot down the aircraft in Irish airspace.

Senior Irish Air Corps officers raised concerns about the legalities of the agreement. Under the 1944 Convention on Civil Aviation only an Irish officer would have standing under international law to shoot down a civilian airliner, the government was advised.

“That was certainly a seriously held concern at Air Corps level,” says Michael Mulqueen, professor of policing and national security at the University of Central Lancashire, who interviewed various defence officials about these concerns as part of his research. “I have always been surprised that the RAF has been willing to accept that risk,” he told The Irish Times.

As far as he is aware the legal situation has not changed in the intervening years.

According to those who spoke to Mulqueen, Irish officers raised concerns that scrambling UK fighters to intercept hijacked aircraft over Ireland might cause the terrorists to “go in glory”. In other words instead of trying to reach their intended target in the UK or further afield the attackers, once intercepted, would settle for a backup target such as Leinster House or Áras an Uachtaráin.

These concerns were set aside and the updated agreement was again approved by Cabinet. Over the subsequent years the memo would be reapproved on a regular basis by Ministers, usually with little to no discussion. Occasionally it was cryptically alluded to in the Dáil. In 2003 minister for defence Michael Smith, responding to questions about how Ireland would deal with a September 11th type attack, said “it is clear that outside assistance would be required”.

In 2005, when asked if the RAF would intercept and aircraft over Ireland, taoiseach Bertie Ahern replied there is “co-operation and a pre-agreed understanding on those matters”.

One source recalls that in recent years, Shane Ross, who served as minister for transport between 2016 and 2020, was one of the few Cabinet members to raise concerns about the nature of the agreement, including its secret nature and its impacts on Irish sovereignty and neutrality. Ross was in favour of making the agreement a matter of public record but he did not get his way. He declined to comment this week.

The Department of Foreign Affairs said that it “does not comment on issues concerning arrangements for national security”.

In the years after September 11th, as fears about further terrorist attacks by hijacked airlines failed to materialise, air defence again faded into the background. For government and defence officials the only time it was of real concern was during EU summits in Ireland or in the run-up to the State visits of President Barack Obama and Queen Elizabeth in 2011, all of which required massive security operations.

Russian Bomber

By this stage Irish air defence capabilities were arguably worse than ever. While it still had the point defence offered by the L/70 and RBS-70, the only aircraft it possessed which was remotely capable of air-to-air defence was the Pilatus PC-9, a propeller-driven trainer acquired by the Air Corps in 2004, shortly after the last jet trainer was retired.

To the untrained eye these eight aircraft, which still form the entirety of the Air Corps’ air combat capability, resemble something which might have been used in the Battle of Britain. Indeed, according to Mulqueen, the aircraft is comparable to those used by the big combatants towards the end of the second World War. “There are late-stage trainee pilots from RAF flying out of Holyhead in trainer jets that are faster than the very best performance the Irish Air Corps can muster,” he says.

Those who have flown the PC-9s are somewhat more positive. “They are equipped with two 0.5 inch machine guns on either side of the wing which are targeted using the heads up display,” said retired Air Corps pilot Kevin Phibbs. “So it’s very capable of intercepting something slow-moving like a Cessna (a small four-seater plane) or a helicopter.”

The main role of PC-9 pilots is to train Air Corps cadets who then move on to other aircraft but once a year they carry out air-to-air exercises. “It was the most enjoyable flying I’ve done,” recalls Phibbs.

But for anything faster than a small private aircraft the PC-9 is all but useless, he concedes, partly because of its top speed of 500kph and effective operating altitude of 10,000ft.

Technically the aircraft’s service ceiling is 25,000ft but, according to Phibbs, “operationally it would be useless at that altitude”. Most commercial airlines operate at between 33,000ft and 42,000ft.

There are other, non-technical, reasons the PC-9 is of limited use. The use of deadly force by Defence Forces personnel is governed by a regulation known as COD6 which lays out in specific detail under what circumstances a weapon can be used. In the view of some Air Corps personnel, COD6 does not give pilots the legal authority to use deadly force no matter what the circumstances.

“You couldn’t justify shooting somebody down as a pilot based on that legal authority,” said Phibbs. That means during the visit of Queen Elizabeth “we had aircraft up there which were armed but which were never going to release any weapons”.

This means that by some interpretations neither Irish or British officers have legal authority to use lethal force over Ireland.

This was not an issue last month during the visit of President Joe Biden purely because at that time the Air Corps was unable to deploy PC-9s at all due to resourcing issues, sources said. Added to that was the fact that the Giraffe Radar system, which is used to guide the Defence Forces’ limited ground-based air defence systems, is by now considered obsolete due to its age.

Today Ireland is probably more dependent on the RAF for air defence than at any point since the first agreement in 1952. It is a situation which was highlighted multiple times since 2015 when the RAF has had to scramble Typhoon jets on several occasions to intercept Russian strategic bombers operating off Ireland’s west coast. The Russian aircraft were flying with their transponders turned off, meaning they were invisible to commercial aircraft and posed a significant safety risk.

In a damning 2022 report the Government-appointed Commission on the Defence Forces concluded that Ireland “has no air defence capability of any significance”. According to the Air Corps’ submission to the commission, the lack of an intercept capability is “as a big gap in the State’s overall defence capability”.

The Government has accepted some but not all of the commission’s recommendations in this area. It has agreed to purchase a primary military radar which will allow the Defence Forces to at least see what is flying in Irish airspace. However, for now it has stopped short of committing to the most ambitious recommendation – the purchase a squadron of jet interceptors which would allow Ireland to police its own skies.

At the same time renewed questions are being asked about the State’s secret agreement with Britain, mostly notably by Independent Senator Gerard Craughwell, a former member of both the Defence Forces and the British army. The Galway Senator has taken a High Court case arguing such an agreement is unlawful and unconstitutional without approval by the Irish people in a referendum.

Central to Craughwell’s case will be the constitutional provision stating that “every international agreement to which the State becomes a party shall be laid before Dáil Éireann”. He may also rely on an obscure memo produced in 1947 by Michael Rynne, the legal adviser at the Department of External Affairs, the precursor of the Department of Foreign Affairs. Rynne said that under international law the Government can enter into an alliance with another country even if it is completely secret. However, such action would still be unconstitutional, Rynne added.

So far the State’s defence to Craughwell’s action has been to argue he has no standing to take the case. Behind the scenes some officials believe they have no case to answer as the RAF arrangement does not meet the legal standard of an “agreement”. “It’s a formal understanding that if we ask for help they will supply it,” said one official.

How does the RAF protect Irish skies?

The RAF’s response to airborne threats is based around its Quick Reaction Alert (QRA) system which allows it to respond to incidents in a matter of minutes at all hours. At the core of the system is the Eurofighter Typhoon, a multi-role fighter capable of travelling twice the speed of sound. Once radar operators based at RAF Boulmer in Northumberland detect a suspicious aircraft a process begins which culminates in Typhoons being scrambled from RAF Lossiemouth in northern Scotland. At the same time aircraft at RAF Coningsby near Lincolnshire are placed on standby should they be required. In recent years the main function of the QRA has been to intercept and observe Russia military aircraft operating around Ireland and the UK before escorting them from the area. Typhoons have limited range but this can be extended through in-air refuelling from another aircraft.

What is the future of Irish air defence?

When the Commission on the Defence Forces came back with its final report in early 2022 it declared Ireland was effectively defenceless on land, sea and in the air. Its most ambitious proposal to address this was for the Irish Air Corps to acquire an “air combat and intercept capability through the acquisition of a squadron of combat aircraft”. Such a squadron, which typically numbers around 12-24 aircraft, would give Ireland its own “quick reaction alert” system, allowing it to respond to threats in its own airspace without relying on the RAF. However, it is not as easy as just buying aircraft. Vast infrastructure would be needed to support an interception capability, including ground controllers, primary radar and a completely new training regime. Training pilots to fly supersonic jet interceptors is no easy task, and it is an area the Air Corp has no experience in. For now the most the Government will commit to is acquiring a primary radar system and changing the name of the Air Corps to Irish Air Force.