took effect on 1 April 1943 and was initially a temporary measure, but became permanent after the war ended. On 6 July 1961, Sir Charles Carter Chitham, a retired policeman of the former British India, laid the foundation stone of the new Wiltshire Police county headquarters at Devizes. Twice in the 1980s, Wiltshire Police officers had to cover for the prison officers of Erlestoke Prison when they went on strike. In 1985, the force was involved in the Battle of the Beanfield, which prevented a convoy of new age travellers, known as the Peace Convoy, from establishing the fourteenth Stonehenge free festival at Stonehenge. The incident led to accusations of a police riot. The police also had to deal with the Greenham Common Women's Peace Camp who were protesting against nuclear weapons being kept in Greenham Common, Berkshire. Most significantly the 1980s saw the introduction of the Police National Computer, Command and Control systems and the HOLMES investigation system. Also a national probationary training programme was introduced in all forces for new recruits. Ports Policing Unit The Wiltshire Police Ports Unit was established in April 2000. It is responsible for policing all non-designated airfields in Wiltshire, making sure that legislation is followed, particularly the Terrorism Act 2000. It also obtains any intelligence on smuggling and contraband. Ports in Wiltshire include Old Sarum Airfield and Clench Common Airfield. Air Support Unit The Air Support Unit was officially created in the spring of 1990, but Wiltshire Police had been renting helicopters since the late 1980s. They experimented with fixed-wing aircraft, a Robinson Beta 22 helicopter and an Aérospatiale Gazelle, but later chose a Bolkow Bo 105 in 1990, which was used for seven years until it was replaced by a McDonnell Douglas MD 902 Explorer. This helicopter was shared with the Great Western Ambulance Service, an arrangement that was seen in only one other area of the country. Besides the pilot, the helicopter carried an observer and a paramedic. The Air Support Unit was based at the headquarters in Devizes, where a hangar was built in 1993. In 2014, the unit was merged into the National Police Air Service, meaning the force no longer owned or operated its own helicopter. From January 2015, the air ambulance function separated into Wiltshire Air Ambulance, a registered charity which operates its own helicopter; the charity leased the Devizes airbase until it moved to a newly