The tri-service exercises have seen around 5,800 troops of 3 Commando Brigade (Royal Marines) supported by 200 vehicles and 20 fast jets, aircraft and helicopters.
The Mission Rehearsal Exercise (MRX), which began on 21 July 2008, is a prelude to the deployment of 3 Commando Brigade (Royal Marines) to Afghanistan in September or October to form Herrick 9 which will replace the current taskforce there.
The exercise is based upon operational conditions likely to be encountered in Afghanistan and is due to continue until 1 August 2008.
It is designed to test the sailors, marines, soldiers, and airmen at individual and command level, using realistic scenarios such as close air support by using fast jets and attack helicopters. A small number of Afghan military personnel are participating in the exercise to add realism and to further promote the close co-operation that exists between the two countries.
The exercise is the culmination of intense sub-unit training designed to shape all the service personnel into one effective military organisation.
Commander 3 Commando Brigade, Brigadier Buster Howes RM said:
"We've been running through command and control during the last few days to ensure that the people involved in the headquarters in Lashka Gah are working together. We'll have 700 personnel there which is many more than the usual 35, so the big challenge is to build trust and understanding.
"The mission for the Brigade will be to defeat the insurgents through the employment of both Military and non-military means. The successful completion of the Mission Rehearsal Exercise is essential if the Brigade is to meet the challenge of this deployment and be fully prepared to face the changing nature of operations in Helmand Province."
Commander-in Chief-Fleet, Admiral Sir Mark Stanhope said:
"I am proud that the Royal Navy supports operations around the world, and this deployment represents the largest Royal Naval Services contribution to land operations for many years."
The Army has been in the forefront of operations in Afghanistan since 2001 and will provide about half of the total manpower to 3 Commando Brigade's deployment.
General Sir David Richards, Commander-in-Chief Land Forces and a former Commander in Afghanistan, said:
"I am very proud of what soldiers on operations in Afghanistan have achieved since we first deployed there seven years ago. As a Commando gunner myself, I am especially delighted that so many soldiers under my command will have the opportunity to work with 3 Commando Brigade (Royal Marines) in Afghanistan later this year."
The Royal Air Force is providing heavy lift helicopters and tactical transportation aircraft to the exercise which in part mirrors their vital contributions to operations in Afghanistan.