The Zero Option.

An ex-SAS officer and an ex member of the Special Boat Services, team up to search for £ 2 million worth of diamonds which go missing when an aircraft is hijacked. Ruthless terrorists seize a London embassy residence. The SAS are called in. There's intense political pressure for a quick resolution. The worst fears of David Barber, the officer in command, are tragically realised. With a brilliant career in ruins, the prospects for ex-Major Barber seem grim until he meets Colonel Patrick Ansell, Managing director of Saracen systems Ltd.