Admiral Sir Alan West, minister in charge of security, is a Falklands veteran and former head of the navy, with a long naval and governmental career.
Admiral Sir Alan West is a veteran of the Falklands War
He was awarded the distinguished service cross for his work commanding the frigate HMS Ardent in the Falklands conflict.
He has been critical in the past of the government on defence matters.
Last year, he warned that lives could be lost among Britain's armed forces if the government failed to invest adequately in defence.
And as head of the navy he reportedly took private legal advice on the legality of the Iraq war - which concluded that the war was legal.
Sir Alan, now 59, joined the navy aged 17, and during his career served on 14 different ships, commanding three of them including HMS Ardent.
The frigate sank in 1982 during the Falklands conflict with the loss of 22 lives, and Sir Alan was the last to leave the stricken vessel.
He was subsequently awarded the distinguished service cross and led the Falklands victory parade upon his return to London.
Since the Falklands, Sir Alan has played a key strategic role in virtually all of Britain's major conflicts and naval manoeuvres.
From 1989 to 1992, he ran naval intelligence for the Ministry of Defence and co-ordinated operations during the first Gulf War.
He was promoted to rear admiral in 1994, and two years later to commander of the UK Task Group which included leading the withdrawal from Hong Kong.
In 1997, he was appointed chief of defence intelligence and deputy chairman of the joint intelligence committee.
The period under his leadership covered strikes against Iraq, the conflict in Kosovo and operations in Sierra Leone.
In 2000 he was promoted to admiral and appointed commander-in-chief fleet, also becoming Nato commander-in-chief East Atlantic and Nato commander allied naval forces north.
He was first sea lord - the professional head of the Royal Navy - and chief of the naval staff, also becoming first and principal naval aide-de-camp to the Queen, from 2002 until 2006.
In 2005 he took a key role in the navy's celebrations to mark the 200th anniversary of the Battle of Trafalgar, acting as chief mourner in a re-enactment of Nelson's funeral.
Sir Alan became the ceremonial head of Southampton Solent University in 2006, when he was installed as chancellor. He has also served as a trustee of the Imperial War Museum.
Earlier this month, Gordon Brown said Sir Alan would carry out a review of NHS recruitment procedures, following the alleged involvement of foreign-educated doctors in the suspected attempted car bombings in London and Glasgow.
Sir Alan was born in April 1948. He was educated at Windsor Grammar School and Clydebank High School, and is married.