Educated at St Peter’s College Oxford, Banfield joined the Royal Navy in 2002. On completion of Britannia Royal Naval College, he underwent Fleet training in HM Ships CUMBERLAND, EDINBURGH and MIDDLETON.

Joining the trained strength as Officer of the Watch (OOW) 2 in HMS CUMBERLAND, his first assignment saw him undertake a Caribbean deployment and a period of UK running. In 2006 he was assigned to HMS DARING in build as OOW 1 and then Navigating Officer. This period saw the Ship undertake Contractors Sea Trials, Acceptance off Contract, Phase 2 Sea Trials and First of Class Flying Trials. During this assignment he had the privilege of navigating the first Type 45 to enter Portsmouth. Six months in Basra followed as the United Kingdom Liaison Officer to the United States District South, Iraq, working directly for the Defence Attaché in Baghdad. On promotion to Lieutenant Commander, he commenced Principal Warfare Officer (PWO) course in 2010. Graduating in 2011, he undertook a 14 month assignment as Operations Officer and PWO-U in HMS SUTHERLAND which included generation for and execution of a Gulf (KIPION) deployment. In early 2013 he was selected to become the Junior Warfare Officers’ Career Manager, a role he executed until early 2014.

He assumed Command of his first Ship, HMS SEVERN in July 2014 deploying on the Atlantic Patrol Task (North) in the Caribbean for eight months, the first time this deployment had been undertaken by an Offshore Patrol Vessel. Relinquishing Command of HMS SEVERN in December 2015 he assumed Command of HMS CLYDE from January to August 2016. He was appointed MBE in the 2016 Queen's Birthday Honours list and promoted to the rank of Commander in June 2016. He assumed Command of HMS IRON DUKE in November 2016. During his Command, Banfield led IRON DUKE through a BALTOPS deployment as well as undertaking Carrier Strike exercises with the USS GEORGE BUSH. A brief period as Commander of the Royal Navy Presentation Team followed prior to attending ACSC. On graduation he joined the MoD in the Finance and Military Capability, Capability Strategy team. This busy period saw planning for and implementation of the Integrated Review. After two years in this assignment Banfield assumed the role of DACOS (Ops) in November 2021 on promotion to Captain. Completing his time in the Maritime Operations Centre in Oct 2023, Banfield attended HCSC 24 prior to assuming the role of Commander SATURATED in May 2024.

Banfield is married to Georgina and has two young daughters. He is a Liveryman of the Worshipful Company of Shipwrights and enjoys sailing and cricket.