The headline that the advertising (and political) world never thought it would see appeared in Campaign last week: "Labour turns to Saatchis". Saatchi & Saatchi, the advertising agency so integrally associated with the Conservative Party, in particular the three successive electoral victories of Margaret Thatcher, had been appointed to handle the Labour party's advertising account in the next election.

Thirty years ago, Saatchi & Saatchi made history with a political poster that is probably the most effective ever produced. It showed a dole queue snaking out from an employment office and disappearing into the distance. The title read: "Labour isn't working", and underneath, in smaller type, "Britain's better off with the Tories". It was to change the course of politics in Britain, end the career of Prime Minister Jim Callaghan, and usher in the Thatcher era and 18 years of Tory rule.

Of course, the Saatchi & Saatchi of today is not the Saatchi & Saatchi of 1978. Then, it was a young, ambitious and trendy agency that had been founded only eight years before by two remarkable Baghdad-born brothers, Charles and Maurice Saatchi. Neither was remotely interested in politics. To them, the Conservative party was simply another account – albeit a high-profile and prestigious one – that they would run like any other.