 Large numbers of journalists were on the scene quickly and were moved into a holding area to the west of the front of the embassy , while dozens of Iranian protesters also arrived near the embassy and remained there throughout the siege . Shortly after the beginning of the crisis , the British government 's emergency committee COBRA , was assembled . COBRA is made up of ministers , civil servants and expert advisers — including representatives from the police and the armed forces . The meeting was chaired by William Whitelaw , the Home Secretary , as Margaret Thatcher , the Prime Minister , was unavailable . The Iranian government accused the British and American governments of sponsoring the attack as revenge for the ongoing siege of the US Embassy in Tehran . Given the lack of co @-@ operation from Iran , Thatcher — who was kept apprised of the situation by Whitelaw — determined that British law would be applied to the embassy , despite the Vienna Convention , under which the embassy is considered Iranian soil . 
