By Nikola Zukalová – Tensions between the United Kingdom and Iran have, again, been mounting over the past week. However, the two countries have a history of maritime tensions in the Arab Gulf. Here are a few of the more noteworthy episodes:

1. 21 June 2004—Iran detained 8 British Royal Navy sailors in the Shatt Al-Arab waterway between Iran and Iraq on their way to Basra. Islamic Revolutionary Guard Corp Naval (IRGC-N) forces and held them captive for three days, claiming that they crossed into Iranian territorial waters. That claim was later disproved and evidence was provided showing that the British vessel remained in Iraqi waters.
2. 23 March 2007—IRGC-N forces captured and interrogated — for nearly two weeks — 15 Royal Navy personnel from the HMS Cornwall which had been conducting a search operation of a vessel suspected of smuggling during their patrol in Iraq’s waters. The Royal Navy sailors were paraded and mocked on Iranian television.
3. 28 April 2015—IRGC-N seized a crew of a Marshall-Island’s flagged container ship, Maersk Tigris, including one British national, in the Strait of Hormuz allegedly because of a legal dispute between the Danish company, Maersk, which chartered the ship, and a private Iranian company.

The Latest Round of Escalations

The latest bout of maritime tensions between the UK and Iran commenced on 4 July 2019, when the British Royal Marines seized an Iranian tanker, Grace 1, near Gibraltar. The ship is suspected of carrying over 2 million barrels of Iranian crude oil to Syria, potentially breaching the European Union sanctions on Syria. In response, Iran summoned the UK’s Ambassador in Tehran and demanded the vessel’s immediate release. Iranian officials threatened to retaliate by seizing a British tanker if Grace 1 was not released. The UK government raised the warning for 15-30 British flagged ships operating daily in the Gulf on the highest alert following an attempt by three IRGC-N vessels to interdict a UK commercial vessel, the British Heritage, on its way to the Strait of Hormuz before they were ordered to leave the area by the Royal Navy’s frigate, HMS Montrose, which fixed its guns at them. To guarantee the security of British ships, the United Kingdom decided on Friday, 12 July to despatched a second warship, HMS Duncan, to the Gulf.