The 5th/7th Battalion, The Royal Australian Regiment (Mechanised) (5/7 RAR [MECH]) was a mechanised infantry battalion of the Australian Army. The battalion was based at Robertson Barracks in Holtze, Northern Territory and formed part of the 1st Brigade. It was formed in 1973 by linking both the 5th and 7th Battalions of the Royal Australian Regiment together and was disbanded 3 December 2006, as part of the expansion of the Australian Army, when the 5th and 7th Battalions of the Royal Australian Regiment were delinked into two separate battalions once again. History 5/7 RAR was formed on 3 December 1973 at Holsworthy Barracks in Sydney by the amalgamation of the 5th and 7th Battalions of the Royal Australian Regiment to form a single light infantry battalion. This was the result of reductions in the size of the Australian Army following the Vietnam War. Throughout the battalion's history 5/7 RAR formed part of the 1st Brigade. In January 1975 the battalion deployed to Darwin as part of the clean-up following Cyclone Tracy. Between 1976 and 1978 5/7 RAR trialed a mechanised infantry organisation using M113 armoured personnel carriers. The value of this mechanisation was demonstrated when the battalion was able to quickly respond to the Sydney Hilton bombing in 1978 by guarding the route between Holsworthy and the site of the Commonwealth Heads of Government Regional Meeting at Bowral. While the mechanisation trial was judged a success, it was decided that only one of 5/7 RAR's companies would be mechanised, with the mechanised role rotating between the battalion's rifle companies every 12 months. The battalion was fully mechanised in 1984 and in 1986 the battalion's official title was changed to 5/7 RAR (Mech). In 1999 5/7 RAR relocated from Holsworthy to Darwin. Later that year the battalion made its first operational deployment when it deployed to East Timor as part of INTERFET and transitioning in February 2000 as the 1st AUSBATT of the UNTAET mission. This deployment proved highly successful, with 5/7 RAR providing the force with a powerful and highly mobile battalion. After a seven-month tour, the battalion returned to Australia shortly after ANZAC Day 2000. 5/7 RAR served a second tour in East Timor between October 2002 and May 2003, though it operated largely as a light infantry battalion on this deployment. The deployment also included a company of General Reserve soldiers, drawn largely from the Royal Victoria Regiment