And then came the Bruges speech in September 1988 and the birth of Thatcher Mark II. When it was delivered, the mandarins in the Foreign Office and those on the Tory front-bench who were heirs of Heath, in respect of Europe, understood that Margaret Thatcher's new position was a direct challenge to the established order. Perhaps feeling guilty that she had gone much further than was wise in agreeing to hand over more powers to Brussels, she scandalised other European leaders by warning of the perils of further integration.

What is often forgotten, however, is that the Bruges speech was a direct response to the new and aggressive campaign for a "social Europe" emanating from Brussels. The prime minister had been infuriated by a series of provocative speeches that summer made by Jacques Delors, then President of the European Commission. He had rounded off with an address to the Trades Union Congress (TUC) in September 1988 that helped to complete the Labour movement's transition from euroscepticism to pro-Europeanism. Europe, Delors suggested, promised an alternative way of securing worker protection and satisfying the collectivist impulse that had been thwarted in Britain by Thatcherism.

The Foreign Office, which (it has been claimed) had privately urged the TUC to invite Delors, was appalled: not by the federalist speech of the President of the Commission in Bournemouth but by the prime minister's daring intervention in Bruges. For committing such an insurrectionist act, Mrs Thatcher would somehow have to be dealt with. Two years later, with the failure of her reform of local government finance (the so-called poll tax) and her increasing difficulties with Cabinet colleagues available as a cover, a plot was hatched and she was taken out by an alliance of largely europhile Tory ministers.

It is illuminating to watch footage of the event in the Commons on October 30, 1990, which led directly to her ousting. Her famous outburst ("No, no, no!") came when she was taking questions after making a statement on the previous weekend's Rome summit, at which she had been ambushed on the question of European Monetary Union. She was viscerally opposed to a single currency, although to maintain Cabinet unity she had been boxed into accepting British membership of the Exchange Rate Mechanism (ERM), which fixed the pound within agreed parameters in relation to other European currencies — in practice, the Deutschmark.