he dedicated the next few years to designing the uk ’ s first electronic stored program computer. and here is an image of that invention, along with the diagrams turing drew when designing it. the ace pilot machine, although much larger than anything we would use today, was one of the world ’ s first computers. recognising the potential for computers to revolutionise the world around us, turing delivered his now famous quote, when describing the ace machine. “ this is only a foretaste of what is to come, and only the shadow of what is to be ”. he has turned out to be prophetic. and this is reflected in one of the key security features of the note – a two colour foil featuring a microchip image over the main see - through window. within this are two gold foil squares, which change between a pound symbol and the number “ 50 ” when tilted. above and below the micro - chip image are green metallic sunflower shapes, and on the back of the note, a red foil patch containing the letters “ at ” is based on the image of a sunflower head. these sunflower images reflect turing ’ s ground breaking morphogenetic work. this new branch of developmental biology which turing pioneered, was the study of algorithms underpinning the formation of patterns in nature. the way a leopard ’ s spots develop into patterns, or the way the seed heads on a sunflower spiral. turing found a way to predict these using maths. here, also, we see him laying the foundations for a new scientific field. his contributions to britain ’ s war effort and its scientific status, make the circumstances of his own death all the more poignant. though guarded about his private life, turing ’ s sexual orientation wasn ’ t a complete secret at the time. he was arrested under indecency laws in 1952, after the police learned of his relationship with another man. the tragic events surrounding this arrest would eventually lead to turing taking his own life, at the age of just 41. in 2017 the turing law was passed in memory of alan, pardoning all men who, like him, were convicted based on their sexuality. another legacy for which alan turing can be remembered. the turing £50 completes our family of polymer banknotes, which already include the £5, £10, and £20 pound notes. these polymer notes are more secure than their paper predecessor, and i'm very pleased that we have made this important transition. banknote

the rt hon sir edward george : macro - economic policy and monetary stability speech by the rt hon sir edward george, governor of the bank of england, at the euromoney bond investors'congress, london, 19 february 2002. * * * thank you padraic for that kind introduction and for honouring me with the euromoney lifetime achievement award. it's nice to be prompted to recall some of the good times - and some of the not so good times in the course of my career at the bank of england which i think of not so much in terms of achievement but of lifelong learning. we've come a long way since 1962 - both nationally and internationally - from different starting points certainly, and moving in fits and starts, at varying speeds and to varying degrees, in a process of continuing, indeed accelerating, change. but standing back and trying to look through the confusion of short - term events, i would pick out three broad trends for comment this morning. the first relates to macro - economic policy, where the earlier emphasis was very much on short - term demand management designed to manage the perceived trade - off between growth and employment, on the one hand, and inflation and a manageable balance of payments position, on the other. monetary policy was used in conjunction with fiscal policy and supported with various forms of direct control to pump up demand, when the economy declined and unemployment rose, until inflation and the balance of payments threatened to get out of hand, at which point all the policy levers were thrown into reverse. it was a recipe for short - termism throughout our economies. we gradually learned from experience - perhaps more slowly in this country than some others - that there is no trade - off between growth and stability in the medium and longer term, and that, in managing demand - which of course we continue to do - we needed to pay far more attention to the underlying, supply - side, capacity of the economy to meet that demand. we came to recognise that direct controls merely addressed the symptoms of instability rather than its causes. we realised increasingly that fiscal policy was not well suited to the task of short - term demand management, and needed to be constrained within prudent limits if debt levels were to be sustainable in the medium - and longer - term. and this left a more distinctive and clearly defined role for monetary policy as the primary instrument for maintaining broad balance consistently over time between aggregate demand and underlying supply. all this has become the accepted wisdom just about everywhere