About us

We oversee all defence nuclear business, excluding operations, following commitments made in the 2015 Strategic Defence and Security Review.

Our mission is to keep safe and capable submarines at sea today and in the future. The UK needs a capable and credible nuclear deterrent to successfully deter the most extreme threats to our national security and way of life.

Defence Nuclear consists of the people, equipment and infrastructure required to make that happen.


Julian Kelly, our Director General, is accountable to the Permanent Secretary, Stephen Lovegrove, for the performance of Defence Nuclear.

We are responsible for:

  • one of defence’s 7 military tasks, providing nuclear deterrence
  • sponsoring the Defence Nuclear Enterprise
  • managing the Defence Nuclear portfolio
  • advising on UK nuclear policy, planning and international co-operation on nuclear matters


Our priorities for 2018/2019 are:

  • continue work on the Dreadnought submarine programme
  • maintain our nuclear warheads and plan for the future
  • continue to build the Defence Nuclear Organisation and develop nuclear skills across our teams

Read our nuclear deterrent policy documents.

Who we are

Defence Nuclear is the seventh Top Level Budget (TLB) in the Ministry of Defence, alongside the Royal Navy, Royal Air Force, British Army, Joint Forces Command, Head Office and Corporate Services, and the Defence Infrastructure Organisation. Each ‘TLB holder’ is responsible for the performance of their organisation, ensuring that they deliver agreed outcomes as effectively and efficiently as possible.

Our head office is based in Main Building, London, but we have staff spread across 3 other sites:

  • Bristol (Abbey Wood)
  • Scotland (Coulport)
  • Reading (Aldermaston).

Defence Nuclear is made up of around 300 people, split into 3 areas:

  • resources and policy
  • submarine capability
  • warhead directorate

We cover all necessary areas to provide a safe, credible and capable nuclear deterrent programme. Our staff are engaged in:

  • scientific research
  • delivery of nuclear warheads
  • procurement of submarines
  • provision of specialised infrastructure
  • nuclear disposal.

As well as sustaining specialist skills, conducting assurance and emergency response arrangements.

The UK’s nuclear programme is a key priority for the Government. The Dreadnought submarine programme (just one element of what we do), is one of the UK’s biggest projects in a generation. It is also one of the most complex undertaken by British industry, equivalent in scale to Crossrail, High Speed 2 or the 2012 Olympics.

With the Vanguard Class of nuclear armed submarines due to leave service in the 2030s, we now need to build four new submarines to replace them – the first of which is Dreadnought. Defence Nuclear also ensures the UK has reliable and safe nuclear warheads that have sufficient impact and performance to enable the Prime Minister’s deterrence criteria to be met.

Recognising the complexity and challenging nature of what we do, delivering this huge programme of work is not solely down to Defence Nuclear. We partner closely with Navy Command who operate the UK’s submarines, and with the Submarine Delivery Agency (SDA) who are responsible for delivering our submarine programmes.

The Atomic Weapons Establishment, who provide and maintain our nuclear warheads, and our main industry partners (BAE Systems, Rolls-Royce and Babcock), play a vital role in sustaining the UK’s nuclear programme. Together, we are committed to a shared purpose of delivering the work required to support the UK’s independent nuclear deterrent.