Dutton originally applied to join the
British Army but failed the selection process. He applied to join, and was commissioned into, the
Royal Marines in 1972. He was promoted to acting
lieutenant in 1975, before being granted the substantive rank in 1976, with seniority from October 1975. He served as a signals officer in the
Falklands War and, after holding a variety of staff positions in the junior ranks, was promoted to
major in 1990. In 1996 he assumed command of
40 Commando, in which position he served on
manoeuvres in Asia and South Africa. "Keen" The brigade had a tour of duty in Iraq in early 2003, at the very beginning of the
Iraq War. Dutton led 3 Commando, as well as supporting units from the
Royal Engineers,
7 Armoured Division,
16 Air Assault Brigade along with troops from multiple other nations, including
US Marines, the first time American troops had been under the operational command of a British officer since the Second World War. Royal Marines from 40 Commando under Dutton's overall command, along with
United States Navy SEALs, secured oil fields on the
Al-Faw Peninsula to prevent them from being burned in the first days of the ground operation, after which 40 Commando and others from 3 Commando Brigade moved up the peninsula and took the port city of
Umm Qasr, where they encountered resistance into the fifth day of the ground campaign. Dutton also commanded the brigade through heavy fighting on the outskirts of
Basra and commented that the fighting had been more intense there than predicted, saying "the planning assumption had always been that the advancing coalition forces would simply sweep past Basra and it would implode by itself". Dutton's calmness during the invasion prompted journalist
Tim Butcher, who reported on the war while attached to 3 Commando Brigade, to describe him as "a lean, thinking man with none of the tub-thumping machismo of some officers" and "coldly professional in his job". While still under Dutton's command in late 2003, 3 Commando Brigade conducted the Royal Marines' first visit to
Slovenia, prior to the country's accession to the European Union and NATO, for alpine warfare training led by Slovenian troops and culminating in the five-day Exercise Royal Chamois. With the brigade, Dutton also undertook cold-weather training in Norway in 2004. In 2002, Dutton was given the honorary appointment of
Aide-de-camp to the Queen. ==High command==