Alan William John West, Baron West of Spithead, is a retired admiral of the Royal Navy and formerly, from June 2007 to May 2010, a Labour Parliamentary Under-Secretary of State at the British Home Office with responsibility for security and a security advisor to Prime Minister Gordon Brown. Prior to his ministerial appointment, he was First Sea Lord and Chief of the Naval Staff from 2002 to 2006.

The First Sea Lord and Chief of the Naval Staff (1SL/CNS) is a statutory position in the British Armed Forces usually held by a four star admiral. As the highest-ranking officer to serve in the Royal Navy, the chief is the principal military advisor on matters pertaining to the navy and a deputy to the Secretary of State for Defence. In a separate capacity, the CNS is a member of the Chiefs of Staff Committee and, thereby, a military advisor to the National Security Council, the prime minister and the monarch. The First Sea Lord is typically the highest-ranking officer on active duty of the Royal Navy unless the Chief of the Defence Staff is a naval officer. Admiral Ben Key was appointed First Sea Lord in November 2021.