Plans to create a Royal Marines 'superbase' in Plymouth and Torpoint are set to go ahead, according to the Ministry of Defence.
Amid concerns that two of the city's amphibious assault ships could be axed, as well as up to 1,000 Royal Marine posts, the Ministry of Defence (MoD) has confirmed that Devonport is due to remain an amphibious centre of specialisation.
The affirmation comes following pressure on the Government from Plymouth's MPs.
The Better Defence Estate review, published in November 2016, states that Royal Marines from other bases will be relocated to Plymouth, as dozens of other military bases around the country are sold off.
It also cited Devonport as a specialist centre for hydrographic and meteorological centre, as well as the only base in the UK to refit Royal Navy submarines.
In November it was revealed that Plymouth's amphibious assault ships HMS Albion and HMS Bulwark – two of Royal Navy's most versatile and capable ships - could be scrapped as part of the ongoing National Security Strategy and Strategic Defence and Security Review.
The city's third amphibious vessel, the current Royal Navy flagship HMS Ocean, is due to be commissioned early this year and has reportedly been sold to the Brazilian Navy.
The Herald, alongside the Western Morning News and Plymouth City Council, has campaigned for the ships to be saved.
The MoD has given reassurance that Plymouth is set to remain an amphibious centre.
In regard to the ongoing defence review, the spokesperson added: "In the face of intensifying threats, we are contributing to the cross-government review of national security capabilities and looking at how we best spend our rising defence budget to protect our country.
Mr Mercer asked for reassurance that Plymouth would remain the centre for the Royal Marines, as outlined in the Better Defence Estate Review, at a House of Commons Defence Select Committee meeting in November.
The Deputy Chief of the Defence Staff replied that it would.
The Conservative MP said the Better Defence Estate Strategy would benefit Plymouth.
"The Better Defence Estate Strategy is a good thing for Plymouth," he said.
The Better Defence Estate report states that 24 Engineer Regiment Royal Engineers and Commando Logistics Regiment members from Chivenor Airfield, Devon, and 40 Commando Royal Marines from Norton Manor Camp in Somerset will be consolidated in the Plymouth and Torpoint area at HM Naval Base Devonport and HMS Raleigh.
HQ 3 Commando Brigade and 30 Commando, Royal Marines currently based at Stonehouse Barracks, and 29 Commando Regiment Royal Artillery, currently based at the Royal Citadel, will also be relocated to the 'superbase'.
Stonehouse Barracks is due to be sold off and the Royal Citadel, currently leased by the MoD from the Crown Estate, will be vacated in the early 2020s.
Last year it was anticipated that the commandos currently based at the two Plymouth bases would be transferred to RM Tamar, which sits within the naval base.
Opened by Prince Harry in 2013, RM Tamar is home to the Royal Marines' amphibious training squadron – 10 Training Squadron – and 539 Assault Squadron.
About 300 military personnel, including marines and civilian staff, are based at RM Tamar, which cost £30 million to build and has state-of-the-art facilities, including offices, workshop and maintenance space, a boat park, jetty, slipway, craft hoist and marina.
More than 670 Royal Marines are currently based at Stonehouse Barracks.