The Royal Marines from 3 Commando Brigade are working alongside their French counterparts to develop the new Combined Joint Expeditionary Force - a specialist amphibious fighting unit that can take part in a range of land operations.
Transferred from Royal Navy warships such as HMS Bulwark - the fleet flagship, the Marines are injected onto the land via boat or helicopter from where they can go directly into combat with land forces.
Although the main training objective is to prove that the two countries can work side-by-side, and can also integrate their equipment and communications, Exercise Corsican Lion comes under Cougar 12 - a three-month deployment involving four Royal Navy warships, one Royal Fleet Auxiliary ship and naval and RAF air power.
Cougar 12 has more than 3,000 Royal Marines, sailors and airmen taking part - with the sole objective of testing the capability of the Response Force Task Group, a rapid reaction force that can be deployed to deal with unexpected world events such as the Libyan conflict.
The Marines, lead by Brigadier Martin Smith, make up the Lead Commando Group (LCG), whose skills are currently being put to the test. Brigadier Smith said: "It is an incredibly versatile force and our burgeoning interoperability with the French further proves this. The quality of Royal Marines Commandos and French Marines delivers a highly effective first response capability which is optimised for early entry operations."
Working together gives the UK and France the flexibility to take part in a range of operations in support of government objectives. Amphibious forces can conduct regional engagement, maritime security and evacuation operations, and deliver humanitarian aid or carry out disaster relief, all whilst remaining ready to fight if need be.
The Royal Navy is required, as a result of the Strategic Defence and Security Review, to generate a Lead Commando Group (LCG) drawn from 3 Commando Brigade to be kept at very high readiness to respond to crises around the globe.
The current LCG is made up of Marines from 45 Commando, 30 Commando Information Exploitation Group, 539 Assault Squadron, 29 Commando Regiment Royal Artillery and 24 Commando Engineer Regiment.