Armed Forces - Royal Navy - n3a1 - Royal Naval Vessels - Strategic Deterrent - Trident Successor Programme




The United Kingdom's Strategic Deterrent is undertaken by the Royal Navy and submarine launched ballistic missiles (SLBM) have been installed in Royal Naval submarines since the late 1960s. Operational patrols commenced in 1969 with US Polaris missiles embarked.


Vanguard Class Submarine

The first class of UK SSBN (Nuclear Powered Ballistic Missile Submarine) was the Resolution Class with four boats - this class has now been replaced by the larger Vanguard class armed with 16 x US Trident II D5 missiles.

Each missile has the capability of carrying up to 12 x MIRV (Multiple Independently Targeted Re-entry Vehicles) warheads, making a possible total of 192 warheads per submarine.

The UK is believed to have purchased 58 x Trident 2D-5 missile bodies from the United States and the range of the missile is believed to be in excess of 9,000 km with a CEP (Circular Error of Probability) of about 100 metres. It is believed that in UK service the Trident II D5 carry eight warheads per missile.

These large submarines displace over 16,000 tonnes and have a length of 150 metres. The three decks offer accommodation for the crew of 130 which is unusually spacious for a submarine. Good domestic facilities are provided for the crew and the air purification system enables them to remain submerged for long periods without any outside support. Each submarine has two crews known as Port and Starboard - when one crew is away on patrol the other crew is training or taking leave.

Following the 1998 Strategic Defence Review (SDR), the UK MoD revealed that it was no longer necessary to have a stockpile of 300 warheads and that the stockpile was being reduced to 200 operationally available warheads. In addition, the 58 missile bodies already purchased would be sufficient to maintain a credible deterrent. The MoD confirmed that there would be one SSBN on patrol at any one time but carrying a reduced load of 48 warheads.

In order to ensure one ship of a class to be available for operations, it is normally reckoned that three should be in service one in repair or refit, one preparing for operations or working up and one fully operational. Four submarines provide a guarantee of one operational at all times.









15,980 tons dived


1 x Rolls Royce pressurised water-cooled reactor supplying steam to two sets of General Electric geared turbines delivering 27,500 shp to one shaft


Speed 25 knots




4 torpedo tubes capable of firing Spearfish Torpedoes


16 Missile Tubes capable of firing Trident D5 missiles



HMS Vanguard (S28)


HMS Victorious (S29)


HMS Vigilant (S30)


HMS Vengeance (S30)


In 2007 the UK Government stated that the current Vanguard Class submarines cannot last indefinitely and would begin to end their working lives sometime in the late 2020s (possibly 2028). A replacement submarine would need about 17 years of development and that early decisions on a replacement were required.

A number of studies are underway to determine the specifics of the solution that will replace the current Trident/Vanguard Class system, with a likely successor being a submarine launched ballistic arrangement (our interpretation of the evidence).

Trident Successor Programme

UK Government policy remains as set out in the Strategic Defence and Security Review 2010, in that a continuous submarine-based deterrent will be maintained and that work has begun on replacing the Vanguard class submarines. The UK MoD is continuing work on the assessment phase of the Successor submarine programme, to inform a Main Gate decision in 2016. Currently (2013) the Cabinet Office is leading a review into whether there are alternative systems and postures that could maintain a credible deterrent.

The Trident Successor programme will be funded from the MoDs core equipment budget and the MoD has also confirmed that once the new submarine comes into service, the in-service costs of the UKs nuclear deterrent, including the costs of the Atomic Weapons Establishment (AWE), will be similar to the current level of around 5-6 per cent of the defence budget.

An initial estimate is that the procurement costs for the complete new system will be in the range of 25 billion for a four-boat solution.

The replacement programme is currently is the Concept Phase and the costs will be refined as experts continue to engage in detailed discussion with industry.

During mid 2013 an Integrated Programme Management Team (IPMT) was in place to manage the delivery of the Successor submarine programme. It comprises about 50 personnel from the Ministry of Defence, BAE Systems Maritime-Submarines, Babcock Marine and Rolls-Royce.

The Integrated Master Schedule (IMS) is the consolidated plan linking all the activities required to deliver the Successor submarine programme and this plan is maintained on a continuous basis. If the Successor submarine programme goes ahead following Main Gate approval in 2016 and proceeds to production, it will sustain thousands of jobs across the UK submarine industry, including businesses at all levels of the submarine supply chain.

The current nuclear warheads will remain viable until the late 2030s and therefore, a decision on the replacement warhead will now be deferred until 2019.

Submarine Service personnel

The latest figures we have for the Submarine Service was 3,478 personnel (638 officers, 299 warrant officers and 2541 other ranks). This figure includes personnel assigned to the six crews for the four Vanguard submarines and submarine service personnel assigned to posts elsewhere in the MoD

Photo Copyright BAe Systems