Submarine sustainment (FMSP)
Sustaining the entire UK submarine fleet
Through the Future Maritime Support Programme (FMSP), we continue to sustain the entirety of the UK’s submarine fleet and support the Continuous At Sea Deterrent.
In 2021 we finalised the FMSP contract with the UK Ministry of Defence (MOD) to continue our support spanning UK naval base operations at HMNB Clyde and HMNB Devonport, alongside UK surface ship fleet and submarine support. This includes delivering through-life support and life extension of Vanguard and Astute Classes of submarine.
Following the completion of the five-year FMSP support contract on 31 March 2026 we agreed a six-month bridging agreement with the UK Ministry of Defence (MOD) to maintain continuity of our naval base and nuclear submarine fleet support services, critical to the UK. The contract bridges to a new long-term agreement which is in the latter stages of negotiation with the MOD. A Letter of Intent from the MOD sits alongside the bridging agreement and reinforces the commitment to a long-term strategic relationship between the MOD, the Royal Navy and Babcock, and the critical contribution that we make to the UK defence capability, including as the sole provider of in-service submarine support to the Royal Navy.
The future agreement supports the Government and Royal Navy’s priorities and aligns with the Strategic Defence Review and Defence Industrial Strategy. It enables increased demand, scope and operations at His Majesty’s Naval Bases Clyde and Devonport and Babcock’s Devonport Royal Dockyard as well as the delivery of the transition from the Vanguard Class nuclear deterrent submarines to the Dreadnought Class.
All of this increases value to our customer and underpins our Strategic Partnering Programme with the UK Government and MOD across a number of critical programmes.
At a glance:
- FMSP is a 5-year contract, worth around £3.5bn
- Includes UK naval base operations at HMNB Clyde and HMNB Devonport
- Includes UK submarine and surface ship fleet support
- We sustain the entirety of the UK’s submarine fleet
- Delivering through-life support and life extension of Vanguard and Astute Classes
Vanguard Class Life Extension Programme
Working closely with a number of agencies and partners, including the MOD, Submarine Delivery Agency, Defence Equipment and Support, commercial partners and ship’s staff, we deliver significant programmes of work for Vanguard-class submarines at our Devonport facility.
These are highly complex and critical programmes, and the life extension activities are platform wide, covering revalidation of the structure and through boat systems. Significant capability enhancements are also installed and integrated, which can include the replacement of motor generators and upgrades to communication systems and strategic and tactical weapon systems.
In 2023, Devonport welcomed Vanguard-class submarine, HMS Victorious, for her planned major refit.
HMS Victorious’ arrival was in tandem with significant investment in the naval base’s facilities, creating additional jobs for people in the region. As well as supporting the maintenance of existing and future classes of submarine, it will also enhance Devonport Dockyard’s ability to deliver major defence projects.
HMS Victorious and the rest of the Vanguard fleet are key components in the UK military’s longest operation – Operation Relentless. Since 1969, at least one nuclear-armed ballistic missile submarine is maintaining the continuous at sea deterrent posture at all times, deterring the most extreme threats to the UK and our way of life. The Vanguard fleet will be replaced by the Dreadnought-class submarines from the early 2030s.