I first met Alan at LSE when I was an MSc student. I was delighted by his clear, amusing and succinct exposition of microeconomics – it was vintage Alan as I later discovered, straight to the jugular of the argument, no pomposity, absolute clarity. Later he agreed to supervise my PhD and he helped me hugely to get started in the world of economics.

When he came to Number 10 in 1980/81, I was fortunate to be able to help him with macro modelling. His style of bureaucracy was an education; memos of crystal clarity and brevity, simplifying complex issues for policy action. It was no wonder Margaret Thatcher relied so greatly on him for economic issues, the dominant ones she faced for much of her period in office.

During that crucial time from 1981-1983 the basics of the Thatcher Revolution were laid – for the control of inflation, for the reduction of unemployment, for the raising of productivity by introducing competition into labour and product markets, not least by privatisation.

Later on Alan was always available to Mrs Thatcher for advice and supported the good things that continued to be done by her team. The ERM episode was a tragedy, about which he repeatedly warned; sadly key colleagues of Mrs Thatcher did not see it and caused a road wreck.

His reappearance in 1989 in Downing Street threatened their gathering conspiracy. The shenanigans that followed achieved their objective of isolating and weakening Mrs Thatcher. Such is politics.

But Alan did his best to keep her show on the road. He remained to the end a great teacher and a loyal friend to her, as to me and so many others.