LONDON — The first of 25 AW101 Merlin helicopters being modified for use by the Royal Marines is about to be released to service, signaling a first step toward a major uptick in the capabilities of Britain's elite commandos. compared with the ancient Sea King Mk4 machines they will be replacing.

"Modification work on the ex-Royal Air Force Merlin is complete and we are waiting for release to service in the next four or five weeks," a spokesman for contractor AgustaWestland said Aug 27.

With a new helicopter poised to start improving air mobility compared with the ancient Sea King Mk4 machines they will be replaceing, the Royal Marines are setting out to boost land mobility and, longer term, possibly sea maneuver capabilities as well.

Last month, the MoD's procurement arm revealed it was evaluating a program to replace part of the commando's fleet of all-terrain vehicles while the Marines themselves are studying the balance of investment across most of the surface craft they employ for amphibious operations.

For the moment, the immediate focus is on the upgraded rotorcraft soon to be handed over to the Commando Helicopter Force, which moves troops and stores from amphibious warfare vessels to the shore as well as transporting them around the battlefield.

It's the first of seven Merlins undergoing an interim modification with a folding rotor head and minor communications and other changes being rushed into operation between now and the second quarter of 2016 as a stop-gap measure as the long-serving Sea Kings are finally pensioned off next year.

Once deliveries are complete, the change will greatly improve the capabilities of British Marines, a significant lift in capabilities according to Doug Barrie, the air analyst at the London-based International Institute for Strategic Studies.

"Merlin's a helicopter which is two generations on from the Sea King, it's a significantly more capable machine," he said.

"It carries more, goes further and gets where it's going faster. With three engines it can continue to undertake a mission even if it losses one of the engines. It's also much more comfortable for the troops," said Barrie.

The Ministry of Defence signed a £330 million (US $504.9 million) deal last year with Merlin-builder AgustaWestland to navalize 25 machines that had previously seen service with the RAF as battlefield support helicopters in Iraq, Afghanistan and elsewhere.

The Merlins transited from the RAF to the Marines in June this year and their move to the Royal Naval Air Station at Yeovilton is due to be completed next year.

The first Merlin scheduled for the full-up modification fit, including an extensive avionics update, folding tail and rotor heads, a stronger undercarriage and other changes has already been was delivered to AgustaWestland's Yeovil factory ahead of upgrading to the Merlin Mk 4/4a standard, said the company spokesman.

The initial operating capability of the fully configured commando Merlin is set for 2018 but the final aircraft is not scheduled to be delivered for delivery until 2022 — a lengthy process dictated more by budget requirements than the lift needs of Britain's 7,000 strong commando force.

The seven interim aircraft will eventually be updated to the full configuration as part of the deal.

With the helicopter program buttoned down, the Royal Marine equipment focus has shifted recently to the land where work is underway on a possible purchase of a new fleet of amphibious all-terrain support vehicles to replace the BAE Systems'-built BV206. machines currently in use.

The BV206, with its two linked tracked units, is highly regarded for its mobility, including an amphibious capability that allows it to swim ashore from Royal Navy amphibious assault ships if required.

The MoD described the BV206s as "obsolete" and in need of replacing.

The purchase of some 233 new machines is in the early planning stage. The MoD's Defence Equipment & Support arm reckons the cost will come in at around £230 million.

The upcoming strategic defense and security review planned for release by the government in the fourth quarter could impact equipment plans but for now selecting a winning contractor remains some 30 months away.

Under If the procurement proceeds on the current schedule, the MoD is aiming for a service entry date of September 2021 and full operating capability by March 2024.

The Swedish-built BV206s fulfill training, logistic support and other roles with the Marines deploying the vehicle's better protected and bigger brother, the BvS10 Viking, for front-line operations.

"Its role will likely be to deliver troops and equipment to the front line as the BV206 has done in the past. Viking moves troops and equipment round the battlespace in a hostile environment," said an MoD spokesman.

Troop-carrying, mortar, ambulance, command, repair and logistic flatbed variants are on the procurement list.

The spokesman said the new amphibious all-terrain vehicles F/ATV and Viking would have the same variants, but continue to have different roles.

Some details of the requirement could start to emerge at a stakeholder day planned to take place on the sidelines of the DSEi defense exhibition, which opens in London Sept. 15.

The MoD spokesman did not rule out other solutions but said the British would likely retain a two-unit configuration for its future all-terrain vehicle.

"The most likely solution is a two-car variant. The new capability needs to interface with in-service equipment such as the landing platform dock and landing craft utility Mk10," he said.

That's likely to put BAE in a head-to-head competition with rival Singaporean all-terrain vehicle supplier ST Kinetics, which already supplies its Warthog machine to the British Army.

Air and land mobility improvements may be underway but for the time being there are no plans to increase mobility on the sea.

A scheme to acquire new high-speed landing craft to take troops and up to five all-terrain vehicles from ship to shore is on hold.

The possible replacement of the LCU MK10 has been talked about for years, with companies like BMT Defence Services and QinetiQ offering designs able to move men and vehicles at speeds in excess of 30 knots instead of chugging around at between 8-10 knots as the current Royal Marine vessels do.

A spokesman for the Royal Marines said plans to take forward other technologies like fast-landing craft have been are deferred pending future capability priorities.

"There is work ongoing to determine future requirements for the landing craft which will inform equipment replacement funding allocation. We can't be more specific on that at this stage," he said.

The Marines are, however, also looking at other craft in the surface maneuver sector as part of force development activity to ensure they have the balance of investment right.

The Griffon 2400TD hovercraft, inshore offshore raiding craft, inflatable raiding craft and the LCUP Mk5 landing craft are all reckoned to be part of the study, although the LCU Mk10 falls outside the work.

"We can't be more specific on this at present but a study of Royal Marines surface maneuver is being conducted," said the spokesman.