A significant further reduction in the visible British army presence in the North is expected in the light of moves on the inspection of IRA arms dumps. A further withdrawal of at least battalion strength is expected in the short term. This may be followed by the dismantling of further military installations.
However, it is likely that the most contentious military installations in south Armagh will remain until there is proof that the IRA is allowing inspection of its dumps and that its arms are out of use.
It is understood that senior British military figures have advised their government that the line of observation posts on hills across south Armagh and the post in Crossmaglen are essential to providing a minimum security cover in the area. Without the posts the military cannot guarantee protection for policing in the area.
There are 13 fortified observation posts mounted on stilts on hills around south Armagh. These are in a line from Drumuckavall to Slievenabala, affording British soldiers clear views into Co Louth and north up to Drumintee.
The security structures in south Armagh also include the Crossmaglen post with its highly intrusive observation platform overlooking the village square. Although the army has ceded land back to the GAA club at the rear of the base, the observation posts remains in place. It is known as the Borucki Sangar, after a 19-year-old private in the parachute regiment who was killed in an IRA booby-trap explosion in the square in September 1976.
It is understood that British military management has advised the British cabinet that removal of any of the posts would mean that it would be impossible to provide adequate protection for police in the area without the influx of thousands of troops and military hardware.
It is also understood that the British military refer to the system of posts and bases in south Armagh as an "irreversible structure". According to military sources, this means that if any of the posts were removed it is unlikely there would ever be the political will to replace them.
Until there is a secure political settlement in the North the military expects the existing structures in south Armagh to remain in place. Military sources say the alternative would be for massive ground troop activity which would mean an equally massive strengthening of the garrison in Northern Ireland.
During the ceasefires in Northern Ireland the military garrison has been depleted to its lowest levels and there is an expectation, in the light of the IRA statement, that this will continue.
No official figures have been released - for security reasons - for the military presence in Northern Ireland. However, military sources have indicated that the real troop strength is at its lowest in 30 years.
The 3rd Brigade or "Security Region South" has five battalions which should have a strength of around 500 but which are believed to be down to between 300 and 350.
The 3rd Brigade includes the Royal Regiment of Fusiliers, based in Bessbrook, south Armagh, and the 3rd Parachute Regiment in Dungannon. It also includes the Scots Guards, on a two-year tour of duty in Ballykinlar, Co Down.
There are also two Royal Irish Regiment (RIR) battalions in the 3rd Brigade Security Region South area. These are the 3rd RIR Battalion, based in Portadown, and the 8th Battalion in Armagh city.
The Royal Irish Regiment (RIR), formerly the Ulster Defence Regiment, is understood to be significantly below its official strength.
Recruitment to the RIR has dropped off since the ceasefires and there appears to be a growing expectation that the regiment will be disbanded or amalgamated fully into the regular British army. High-profile advertisement campaigns have failed to attract young recruits to the regiment.
It was reported last month that an RIR battalion based in Shackleton Barracks, Ballykelly, outside Derry, was being disbanded and its 500 members dispersed to other RIR battalions to bring up their strengths.
Officially, there are 40 British (including RIR) infantry battalions, which would comprise between 20,000 and 25,000 troops available for service in Northern Ireland.
The actual battalion strength is understood to consist of three "rear-based" battalions stationed in England; six "support" battalions stationed in the North on one or two-year tours of duty; three "roulement" battalions on six-month tours, and the six locally-raised Royal Irish Regiment (RIR) battalions. The RIR has one battalion permanently in Britain.
Between half and 30 per cent of the RIR battalions in the 3rd Brigade area are made up of part-time soldiers despite attempts since the formation of the regiment to recruit only full-time soldiers.
Altogether there are probably far fewer than 14,000 troops in the North as many of the soldiers are on secondment to other duties. The British army has undergone substantial cuts in the past decade. It also has a commitment of two brigades, with around 8,000 troops in each, to the NATO peacekeeping force in Kosovo. The Ministry of Defence in London says the number of military installations in the North at the start of the ceasefire process was 105 and that has been reduced to 71 bases since 1995.
It says that military helicopter flights are down by 50 per cent. Helicopter traffic into south Armagh is more obvious than before the IRA ceasefire, the sources say, because there is no longer the need for evasive, low-level flights.