The minister, one of Margaret Thatcher's closest allies, quit after a full day of agonising over his barbed comments about the Germans in the Spectator. At one point Ridley looked set to brazen out the row, but he threw in the towel - on a Saturday too, and in time for our deadline.
2. The Rome summit, 1990
By the end of the first day it became clear that Margaret Thatcher had been ambushed and isolated by the Italian Prime Minister Andreotti (later accused of being a Mafia collaborator). Her defiant anti-Europeanism in the Commons had, within days, produced Geoffrey Howe's resignation.
3. Heseltine's leadership challenge, 1990
Goaded by Tory party chairman Kenneth Baker to put up or shut up, Mr Heseltine did the former, via an open letter to his constituents. The event, which also happened on a Saturday, sealed Mrs Thatcher's demise and John Major's election.
4. John Major's election triumph, 1992
Against expectations Mr Major came through a bruising campaign with a 21-seat majority. At the time one or two commentators declared it to be the end of politics and the beginning of a new era of non-controversial technocratic government. It lasted no more than two months before it was back to usual business.
5. ERM, September 16, 1992.
As the turmoil in the currency markets reached its climax Mr Major summoned the Cabinet "big beasts" to his temporary offices in Admiralty Arch to determine whether or not Britain should quit the ERM, without the benefit even of a Reuters screen. Interest rates were hiked twice before the government was forced into a humiliating devaluation from which it never recovered.
6. The Maastricht Bill, 1992/3.
One hailed as a triumph of Mr Major's negotiating skills, it soon returned to haunt him. In the wake of the Danish referendum, the Euro-sceptic right of the Tory Party went into semi-opposition, finally surrendering the party whip. Not since the 1970s had a government lived, day-to-day, in fear of losing its majority.
7. Labour's leadership election, 1994
John Smith's sudden death made the election of Tony Blair inevitable - so long as he stood. Gordon Brown believed he had a deal, one in which it was understood that he had the first crack at the top job. Pre-election manoeuvring was the key, and the outcome left a bitter legacy.
8. The IRA ceasefire, 1994
Mr Major's one undisputed achievement. Months of secret negotiation with the IRA - all of which had been denied at the time - paid off. The peace process set out on its perilous path.
9. Tony Blair's election, 1997
Few had predicted the scale of the victory, although some pre-election polls called it right. On election day New Labour celebrated its landslide until dawn at the Royal Festival Hall in London.
10. The Stormont agreement, 1998
Against expectations the political parties in Northern Ireland reached a deal, thanks partly to the timely intervention of President Clinton, the physical presence of Tony Blair, and to David Trimble's brave leadership of the Ulster Unionists.