At an event in London on 15 January 2019, Arlene Foster (Leader, DUP), stated that during the Troubles there has not been a hard border between Ireland and Northern Ireland. When asked what she meant by this, she explained: “The borders of the past were there for a completely different reason. They were there to stop terrorists, they were there to stop the flow of Semtex (explosives), as opposed to the flow of powdered milk.”

Foster’s statement is consistent with previous communication by the DUP on a “hard border”.

We have researched the history of Ireland-Northern Ireland border checks—both customs and security, which reveals an interesting evolution

It is true that during the Troubles security checks were installed at the Ireland-Northern Ireland border. These checks were not customs checks; they were intended to stop border-crossing of paramilitaries and explosives.

However, as we explain below, customs checks were in place long before the Troubles started, beginning in 1923 and ending with the creation of the European Union single market in 1993.

The introduction of the customs barrier

The Irish Free State

Less than two years after partition, custom barriers were first introduced by the Irish Free State on April 1923, with a system of duties to be paid on the movement of certain goods, which could only be done by travelling through approved border crossing points where goods could be inspected at an appropriate customs station.

Apart from generating state income, KJ Rankin, research officer at University College Dublin, distinguishes two more reasons why the Irish Free State introduced customs checks. Firstly, it may be seen as a symbolic measure to assert independence. Secondly, it may be viewed as being intended to cause economic pressure on Northern Ireland, hoping to provoke a wish on the northern administration to abolish partition.

Consequently, customs stations were established at the approved routes on both sides of the border. At these points, officers would check goods that people were bringing with them as they crossed the border. The introduction of the customs barrier, however, did not mean it de facto got fully implemented. Over the years, smuggling had become a common practice.

People travelling with motor vehicles also had to use these approved routes if they wanted to cross the border:

“Drivers were required to have a pass book stamped on crossing the border either way and to either do so during daytime hours or pay to cross and be officially stamped back across the border at a specified requested time.” Drivers who did not have their car pass stamped while going back across the border risked having their vehicle confiscated.

British Customs Post, Fathom, 1950s

Stricter customs rules

In the beginning, checks were held on “ordinary merchandise” only; “agricultural, horticultural and dairy produce, peat and turf, and any livestock” could freely be crossed at any point of the border.

This changed during the Economic War at the end of the 1930s, which introduced new restrictions on the movement of livestock and additional tariffs on other agricultural goods were introduced. After the Economic War, both the UK and the Irish government implemented more protectionist economic policies of both governments.

Higher export tariffs and import quotas had its impact on cross-border trade. Livestock could only cross the border between certain hours.

15 approved roads with belonging customs stations came into being in 1923. These crossing points remained more or less unchanged as approved routes for decades. Furthermore, 11 customs stations were placed at the border crossing points of approved railway lines.

At the time of partition, cross border train journeys got interrupted for the investigation of goods, but the railway network as such remained intact. However, the conditions involving the customs system put difficulties to keep running all services. During the late 1950s, the UK government decided to close all but one railway services crossing the border (see video). Only the train line connecting Dublin and Belfast survived.

YearRoad customs stationsRailway customs stations
193815 (14 for livestock)12 (11)
195214 (12)11
196814 (12)1
Customs, Tullydonnell (Louth/Down), 1967

Customs and the border during the Troubles

Anglo-Irish trade opening

Protectionist measurements at both side of the Irish border faded out during the late 1960s, when a trend towards a more open trade started. In 1965, a Free Trade Area agreement between the UK and Irish government was made to lower tariff duties.

Indeed, this trend got strengthened when both countries signed the Treaty of Accession to join the European Economic Community in 1973. Evidently this had consequences for trade between Northern Ireland and the Republic. EEC membership brought back a return to free trade in manufactured goods for the whole island of Ireland. However, this was not the case for agricultural products, meaning that customs stations needed to remain in place.

Securing the border

In contrast to economic openings, the late 1960s also marked the beginning of the Troubles. The “Border Campaign” of the IRA focussed on targets close to the border between 1956 and 1962, such as the customs post of Clones. Additional changes to the nature of the securitisation of the the border only happened when tension escalated at the start of the Troubles. UK government reacted with measures to secure the border. This had drastic consequences for the Irish border at the beginning of the 1970s, making it not only a customs, but also a security barrier.

The border was secured as an attempt to stop the crossing of paramilitaries and weapons towards Northern Ireland, and to make sure paramilitaries would not escape.

Watchtowers and fortifications were built in border areas together with the large presence of the military. Customs stations got armed because officials working there were in danger. The militarisation of the border, combined with the application of EEC rules, ended the decades-old tradition of smuggling goods.

Before the 1970s, it was obligated to cross the border via the approved routes, but only for the import and export of goods. From then, all border-crossing had to go through these routes. Accordingly, army checkpoints were installed along customs posts, so that everyone had to stop before crossing the border, to be questioned about their journey, and having their vehicles investigated.

The blocking of unapproved roads

Many local people knew the ways the border could be crossed apart from approved roads, even on foot or across open fields. British security policy emphasised the need to prevent the smuggling of weapons, and paramilitaries crossing the border using these ways, and as a result all unapproved routes were made inaccessible. The British army blocked many roads by placing large obstacles, digging craters, and blowing up bridges (see photo below).

Locals living around the border frequently felt compelled to re-open unapproved roads themselves, with authorities attempting to reclose these roads again. Others developed new routes, such as tracks across fields. According to Stephen Royle (Queen’s University Belfast) the border, although “thicker”, stayed permeable during the Troubles, “for the border was never fenced or barricaded”.

In 1972, the British Customs and Excise reported over 200 unapproved routes and 17 approved border customs posts at road crossing points. These customs stations became a frequent target for bombing attacks during the Troubles. One of the bloodiest incidents happened at Carrickcarnan, near Newry, where the customs post was attacked by the IRA on 22 August 1972, whereby 9 people died in a bomb explosion. Most incidents happened at the customs station at Cloghore, with 21 registrations of violent incidents, 17 are registered at Lifford Bridge (photo bellow), 13 at Muff, and 12 at Carrickcarnan. These incidents occurred between 1969 and 1994.

Strabane Customs Post bombed. 1972. (c) The Strabane Chronicle

20,000 soldiers?

After her claim about the border, Foster said in her speech that during the Troubles there were “20,000 soldiers in Northern Ireland, and they couldn’t hermetically seal the border”.

In 1972, the numbers of soldiers present in Northern Ireland increased drastically. Following the events of Black Friday on 21 July, when the IRA planted 22 bombs in Belfast, the UK military reacted with “Operation Motorman” just ten days later. New troops were sent to Northern Ireland to re-establish authority in “No Go” areas, bringing the total number of soldiers active in Northern Ireland to over 28,000, the highest level of operating security forces throughout the Troubles.

Other sources say numbers were even higher with more than 30,000 soldiers active during Operation Motorman. This includes 21,800 British regiments and 8,500 UDR soldiers. Foster’s claim could refer to these British regiments, or it could estimate the average number of soldiers during the Troubles.

The end of customs: the European single market

Convention on a common transit procedure

During the late 1980s, a new period of economic overtures started. Part of the 1985 Anglo-Irish Agreement was an attempt “to promote the economic and social development of those areas of both parts of Ireland”.

According to Katy Hayward (QUB), the EEC had a practical impact on the Irish border by “forging change in cross-border economic relationships in Ireland through its structural impact on the significance of the border as an economic and customs divide”. In 1987, the Convention on a Common Transit Procedure was signed, setting out a legal framework of obligations on trade authorities for goods in customs transit between member states. These regulations made it easier to transport goods on the island of Ireland.

The EU Internal Market

More importantly, also in 1987, the Single European Act was signed, laying out the introduction of the European internal market. It was set to come in force in 1993 to create an area of the free movements of goods, persons, services, and capital. The act delivered a new system for taxes on goods. From then on, taxes only needed to be paid in the country where the good was bought.

Closing of customs post at the Killeen Border, Newry. Bobbie Hanvey Photographic Archives

By implementing free trade, customs posts on approved routes at the border became redundant, and were immediately closed on 1 January 1993. Later that year, the EEC was reformed as the European Union by the Treaty of Maastricht, which forms its constitutional basis. It restated “the elimination, as between Member States, of customs duties”.

No internal frontiers?

Both the Single European Act and the Maastricht Treaty promised a union “without internal frontiers”. Some say the removal of customs stations changed the way people “viewed and thought of the border”. However, with the closure of customs posts, only one physical manifestation of the border disappeared.

The approved routes with its customs points were still being used as security checkpoints. The unapproved roads were not opened in 1993, causing some protest at different places on the Island, e.g. at the customs stop of Moybridge. The Irish National Congress started to re-open roads themselves (see video).

The Ireland-Northern Ireland border ceased to be a customs barrier, but still served as a security frontier. The last British military watchtowers along the border were only being dismantled in 2006.


  • 1923: Establishment of the Irish border as a customs barrier for checks on manufactured goods at provided customs stations.
  • 1938: Customs checks also became mandatory for agricultural products and livestocks.
  • 1957: The closure of border-crossing railway services (and their customs stations) due to customs checks.
  • 1970: The Troubles transformed the border into a security barrier. All border-crossings had to be done via the approved routes of the customs stations.
  • 1973: With both Ireland and the UK entering the EEC, customs checks became only necessary for agricultural produce.
  • 1970s-1980s: Customs posts were militarised and used as security checkpoints. They were a frequent target for attacks.
  • 1993: The creation of the EU Single market made the customs barrier disappear. Although checks on goods ended, the customs stations were still being used as safety checkpoints.

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