On 21st of July 1972, a string of 22 IRA car bombs was detonated around Belfast city centre as a result of the escalating Northern Ireland conflict, an event later to be known as Bloody Friday. This was intended to cause maximum damage to the commercial heart of the city.

Security had recently been upgraded in the centre of Belfast due to a bomb attack at the Abercorn Restaurant on Castle Lane on 4th of March 1972 and another on Donegall Street 2 weeks later, and Bloody Friday was a message to the British State that the IRA would not be deterred.

Bloody Friday forced the rapid reconsideration of security in Belfast's city centre in order that business could continue whilst protecting the area from further attacks. 'Operation Segment' was coordinated by the Security Forces, splitting the central area of the city into 7 areas, or Segments, each Segment referred to by a letter.

Segments E and F were sealed off overnight with barbed wire and fencing on 29th of October 1972 followed by Segments A, B, C, D and G on 5th of November.

Vehicular access to the Segments was to be prohibited apart from security and goods vehicles. The Security Forces were also responsible for setting up and manning access gates, searching pedestrians accessing the city centre through the gates and patrolling within the Segments.

The public was informed of the new arrangement by the Security Forces, who published maps and lists of access points through the Belfast Telegraph to help locals navigate the new system. The Army took possession of the Grand Central Hotel on Royal Avenue and used this as their tactical HQ, housing two sub-units and a bomb disposal team - a total of 400 men, making the hotel a major target that required heightened security. To ensure this security, necessary road closures were undertaken in Segment G, a fortified check-point was built, and a protective mesh installed to protect the outside of the hotel from attack.

Pedestrian access to the security Segments was restricted to working hours. At night, the city was closed off to all but security personnel with limited access to residents, business owners and delivery vehicles. Pedestrians leaving the city after hours had to exit through a handful of turnstiles that only permitted one-way movement.

Day to day management of the Segments was overseen by the City Centre Security Committee (CCSC), made up of representatives from the Royal Ulster Constabulary (RUC), Security Forces, Northern Ireland Office (NIO) and city centre traders’ representatives. The CCSC was responsible for monitoring and improving the Segments, and ensuring that business as usual could continue in Belfast, whilst managing security against the increasingly well-organised insurgency.

The 1972 restrictions were deemed successful in stopping car bombers entering the city centre, but they had negative consequences for business. The wire frame surrounding the Grand Central Hotel meant nearby traders suffered from loss of business. People had to pass through multiple gates when moving between Segments when shopping, submit to being searched at each, then undergo further searching when entering each individual shop. Records from the CCSC minutes from early 1973 state that shopping in Belfast was 'a lengthy and frustrating experience for housewives who had to submit every parcel for checking' (The National Archives, file CJ4/1241).