after 31 July 2007 was reduced to a residual level, known as Operation Helvetic, providing specialised ordnance disposal and support to the PSNI in circumstances of extreme public disorder as described in Patten recommendations 59 and 66, should this be needed, thus ending the British Army's emergency operation in Northern Ireland. Role of the armed forces The support to the police forces was primarily from the British Army, with the Royal Air Force providing helicopter support as required. A maritime component was supplied under the codename of Operation Grenada, by the Royal Navy and Royal Marines in direct support of the Army commitment. This was tasked with interdicting the supply of weapons and munitions to paramilitaries, acting as a visible deterrence by maintaining a conspicuous maritime presence on and around the coast of Northern Ireland and Lough Neagh. The role of the armed forces in their support role to the police was defined by the Army in the following terms: "Routine support – Includes such tasks as providing protection to the police in carrying out normal policing duties in areas of terrorist threat; patrolling around military and police bases to deter terrorist attacks and supporting police-directed counter-terrorist operations" "Additional support – Assistance where the police have insufficient assets of their own; this includes the provision of observation posts along the border and increased support during times of civil disorder. The military can provide soldiers to protect and, if necessary, supplement police lines and cordons. The military can provide heavy plant to remove barricades and construct barriers, and additional armoured vehicles and helicopters to help in the movement of police and soldiers" "Specialist support – Includes bomb disposal, search and tracker dogs, and divers from the Royal Engineers" Number of troops deployed At the peak of the operation in the 1970s, the British Army was deploying around 21,000 soldiers. By 1980, the figure had dropped to 11,000, with a lower presence of 9,000 in 1985. The total climbed again to 10,500 after the intensification of the IRA use of improvised mortars toward the end of the 1980s. In 1992, there were 17,750 members of all British military forces taking part in the operation. The British Army build-up comprised three brigades under the command of a lieutenant-general. There were six resident battalions deployed for a period of two and a half years and four roulement battalions serving six-months tours. In July 1997,