The Armilla patrol is the Royal Navy's permanent presence in the Persian Gulf.

The Royal Navy had withdrawn its forces from the Persian Gulf in 1971 in line with the UK's general retreat from imperial commitments. However, tensions in the area remained high and Royal Navy ships were still a frequent sight in the area. In 1980 war broke out between Iraq and Iran. In response to the increased danger to British shipping and other British interests, a Royal Navy escort vessel was sent to the Gulf and at least one has remained there ever since. In addition to the surface combatant, the RN has also maintained an auxiliary of the Royal Fleet Auxiliary in the Gulf.

Typical Armilla patrol deployments last for six months or so, with the supporting RFA vessel sometimes spending an aggregate total of over a year in the area. They are reinforced in times of high tension or British involvement in wartime operations in the area. They have also recently been augmented by a second surface combatant deployed as part of Operation Oracle , the UK's assistance to the United States in its operations against terrorism in the area. However, the Oracle ships typically operate more in the Arabian Sea rather than the Persian Gulf itself.

The largest British presence in the Gulf during the Armilla patrol has been during the two operations against Iraq. In 1991, eight Royal Navy ships supported by a number of RFA vessels were sent to the area. In 2003 over 30 British warships and auxiliaries were involved in the invasion of Iraq. Aircraft carrier battlegroups were also periodically rotated through the area during the 1990s.

Given that international tension in the area shows no signs of decreasing, the Armilla patrol will likely remain a feature of British naval life for many years to come.