The national security adviser (NSA) is the central co-ordinator and adviser to the prime minister and cabinet on security, intelligence, defence, and some foreign policy matters. They are based in the Cabinet Office and work across departments to bring together a coherent national security strategy that fits with the government’s priorities. The national security adviser is secretary to the National Security Council and leads the National Security Secretariat, which supports the National Security Council.
The National Security Council is a cabinet committee established in 2010 which co-ordinates policy decisions across departments, involving ‘national security, foreign policy, defence, international relations and development, resilience, energy and resource security'. 
The National Security Council is supported by the National Security Secretariat. The secretariat co-ordinates cross-Whitehall preparations for weekly National Security Council meetings and the implementation of decisions. This includes working with the prime minister and government departments to set the meeting agenda, providing advice to inform the discussion and minuting decisions made.
The NSA has until now chaired the National Security Council Officials’ Group, which brings together permanent secretaries of departments represented on the ministerial National Security Council. Here they can co-ordinate detail with the heads of the intelligence agencies and follow up decisions that are made in the council.
The current NSA is Sir Stephen Lovegrove, who was appointed in January 2021. He is a civil servant, and was previously the permanent secretary at the Ministry of Defence and the former Department for Energy and Climate Change. Lovegrove is the fifth civil service appointment as NSA.
There is no standard process for appointing national security advisers. Previous appointments have been made by the prime minister without an open competition.
The NSA works closely with the prime minister to advise on a coherent approach to national security policy and the government’s response to major crises.
The NSA leads and co-ordinates security and defence reviews which assess Britain’s future strategic interests and the needs of the military and intelligence systems to meet these goals. There have been reviews conducted in 2010 and 2015, and the new government laid out its intention to conduct a security and defence review in 2020 in the December 2019 Queen’s Speech.
What is the national security adviser's relationship with UK intelligence agencies and international allies?
The NSA has also been responsible for the line management of the heads of the intelligence agencies – MI5, MI6 and GCHQ.
The NSA must also build close international relationships with allies. This is especially important with the international counterparts of the members of the ‘Five Eyes’ intelligence sharing agreement (which the UK is part of alongside the US, Canada, Australia and New Zealand) and other members of the G7.
No. The NSA is assisted in their role by two or three deputy national security advisers. Deputies will focus on specific policy areas, to which they often bring considerable expertise. For example, Julian Miller had experience in the Ministry of Defence, and as deputy NSA under Kim Darroch, he had specific responsibility for defence issues in the National Security Secretariat.
The national security adviser had been responsible for the Conflict, Stability and Security Fund, but from 2017 the role has been passed to the Deputy NSA  .
The delegation of responsibilities to the NSA deputies became increasingly important since 2018, when Mark Sedwill as national security adviser combined the NSA role with cabinet secretary and head of the Home Civil Service. This led to accusations that he was unable to give the role his full attention.
The post of NSA was created by David Cameron in 2010 at the same time as the National Security Council was set up. It was formed to strengthen the co-ordination capacity within the centre of government on national security.
The NSA combined pre-existing advisory and co-ordination functions to give a more focused channel for security advice. This included roles previously played by the prime minister’s adviser on foreign policy, the head of the Overseas and Defence Policy Secretariat, the prime minister’s intelligence co-ordinator, and some of tasks previously overseen by the cabinet secretary and the chair of the Joint Intelligence Committee.
Under the principle of ministerial accountability, it is government ministers who are accountable to parliament for the actions of the government, including those of the officials and special advisers working for them. The NSA is answerable to the prime minister.
But like other senior officials, the NSA can appear before parliamentary select committees in their own right to answer questions on their work. The select committees who scrutinise the NSA’s work are the Defence Select Committee and the Joint Committee on the National Security Strategy.
The Intelligence and Security Committee also scrutinise the work of the NSA and the National Security Secretariat. This body is not a select committee, but a statutory committee set up by parliament to oversee the work of the UK’s intelligence agencies and their co-ordination in the Cabinet Office. This committee has more access to sensitive security information than select committees but reports directly to the prime minister rather than to parliament.
- List of Cabinet Committees and their members as at 29 June 2020, Cabinet Office, 29 June 2020 https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/896093/Cabinet_Committee_list_and_public_ToRs.pdf
- Conflict, Stability and Security Fund: Annual Report 2016/17, HM Government, 17 July 2017 https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/630077/conflict-stability-security-fund-annual-report-2016-2017.pdf
- Conflict, Stability and Security Fund: Annual Report 2017018, HM Government, 18 July 2018 https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/727383/CSSF_Annual_Report_2017_to_2018.pdf