 Home Secretary Willie Whitelaw , who had been chairing COBRA during the siege , was rushed back to Whitehall from a function he had been attending in Slough , roughly 20 miles ( 30 km ) away , arriving 19 minutes after the shots had been reported . He was briefed on the SAS plan by de la Billière , who told him to expect that up to 40 per cent of the hostages would be killed in an assault . After deliberations , Whitelaw instructed the SAS to prepare to assault the building at short notice , an order that was received by Mike Rose at 15 : 50 . By 17 : 00 , the SAS were in a position to assault the embassy at ten minutes ' notice . The police negotiators recruited the imam from a local mosque at 18 : 20 , fearing that a " crisis point " had been reached , and asked him to talk to the gunmen . Three further shots were fired during the course of the imam 's conversation with Oan . Oan announced that a hostage had been killed , and the rest would die in 30 minutes unless his demands were met . A few minutes later , Lavasani 's body was dumped out of the front door . Upon a preliminary examination , conducted at the scene , a forensic pathologist estimated that Lavasani had been dead for at least an hour — meaning he could not have been killed by the three most recent shots , and leading the police to believe that two hostages had been killed . In fact , only Lavasani had been shot . 
