According to the DVD commentary, the film was made with the help of the 22 SAS Regiment at Hereford, although their commanding officer Peter de la Billière had initially refused to help in a pre-production meeting with Euan Lloyd. Director Ian Sharp, who was hired due to Lloyd's liking of his direction in the TV series "The Professionals", was invited to SAS headquarters at Stirling Lines where he met some of the troops who assaulted the Iranian embassy. With the co-operation of the SAS achieved, production moved ahead swiftly.