There will be two frontline squadrons of Apache helicopters in both 3 and 4 Regiment AAC, with 3 Regiment also parenting the Apache OCU, 653 Squadron. One Regiment will be at high readiness at any one time. One of the squadrons will be attached to and/or the new aircraft carriers for expeditionary operations. Another will be attached to the lead armoured battlegroup. However, under Army 2020 Refine, 3 Regiment AAC will be tasked to support the armoured infantry, and strike brigades of 3 (UK) Division and 4 Regiment AAC will support the army's 16 Air Assault Brigade and 3 Commando Brigade of the Royal Marines.