The recent death of the notorious Soviet spy George Blake has reminded me of a documentary film I made many years ago with Sean Bourke, the Irish man who was responsible for springing Blake from prison. Bourke had been befriended by Blake when they shared a cell in Wormwood Scrubs. Blake had been a high-ranking officer in MI6 and the information that he passed on to his Soviet handlers had resulted in the deaths of many British agents in Eastern Europe. In 1961 he had been sentenced to 42 years in prison: one year, it was claimed, for every agent who had died as a result of his treachery.