Admiral Sir Nigel Richard Essenhigh GCB, DL (born 8 November 1944) is a former Royal Navy officer who served as First Sea Lord and Chief of the Naval Staff from 2001 to 2002.

[9] Following promotion to rear admiral, he took up the position of Hydrographer of the Navy in February 1994, and was subsequently Assistant Chief of Defence Staff (Programmes) from March 1996.

[14] He was advanced to Knight Grand Cross of the Order of the Bath in the 2002 Birthday Honours[15] and retired on 3 December 2002.

[20] His son Rear Admiral Angus Essenhigh served as the fourth captain of the aircraft carrier HMS Queen Elizabeth from January 2020[21] and was appointed national hydrographer in July 2023.

[22] On 13 June 2015, after the previous month's general elections, and together with Admiral of the Fleet Lord Boyce, Field Marshal Lord Walker and Air Chief Marshal Sir Peter Squire, he painted the UK Armed Forces as "feeble" and said "We are appeasing our enemies and making the same mistakes as in the 1930s during the rise of Nazism."

He characterised the status quo as "parlous", argued for a review that would be "policy-led" as opposed to "resource-driven" and closed with an appeal for a review that "must demonstrate to potential enemies that Britain continues to be a country that will not be coerced into submission through military weakness when diplomacy fails in the future, as it did in the Thirties.