The boarding team of eight sailors and seven Royal Marines in two rigid-hulled inflatable boats was detained at 10:30 local time, following a boarding operation by the British personnel, by six Guard boats of the IRGC Navy. They were subsequently taken to a Revolutionary Guards Corps base in Tehran for interrogation. On 28 March 2007 the Iranians showed some of the 15 British sailors on television. The British team had been conducting a compliance inspection of an Iraqi ship, under the mandate of United Nations Security Council Resolution 1723. The Iraqi merchantman had aroused suspicion while moving along the Shatt al-Arab/Arvand waterway.Sovereignty over the waterway, and corresponding territorial waters, is disputed between Iraq and Iran. While innocent passage is permitted in each other's waters, boarding and compliance inspections in another state's waters would not be lawful. It was reported that the CTF158, Cdre Lambert, requested advice from the Ministry of Defence but was told to hold fire,
British Prime Minister Tony Blair later said the attitude of the British forces had been "entirely sensible", if they had fired there would "undoubtedly have been severe loss of life".
The United Kingdom says the sailors were on a routine patrol of the area. In accordance with United Nations Security Council Resolution 1723, they had boarded the vessel 1.7 nautical miles (3.1 km) inside Iraqi territorial waters at 29°50.36′N 48°43.08′E. One of the boats remained data-linked to HMS Cornwall throughout this time and the GPS system showed them to be located well within the Iraqi area, though no direct evidence for this was given. This position was later confirmed by the Indian flagged merchant vessel, which had subsequently dragged east on its anchor to 29°50.174′N 48°43.544′E.
Iran's director general for Western European affairs, Ibrahim Rahimpour, said that the British boats had made "illegal entry" into Iranian territorial waters and that the personnel "were arrested by border guards for investigation and questioning". Mohammad Ali Hosseini, Iranian Foreign Ministry spokesman, voiced his country's discontent of what he called "blatant aggression", accusing The United Kingdom of "violating the sovereign boundaries of other states". He further stated that Britain was trying to cover up the incursion and that they should refrain from putting the blame on others.
The US Navy had dispatched 2 Nimitz class aircraft carriers (USS John C. Stennis and USS Dwight D. Eisenhower) carrying more than 100 aircraft (F/A-18 fighter jets) along with 15 other warships to the Persian Gulf. The US Navy maintains that the battle group was dispatched to the Gulf before Iran detained the British sailors, and it was not a show of force in response to Iran's actions.
Britain has the US, EU, Australia, Iraq and other's support. If the Iranians dont release the RN personnel, what will happen? SAS raid, or full war becuase that has been coming for a while now.