Next weekend will be Gordon Brown's worst as Prime Minister. Worse than all his previous worst weekends. Labour will do badly in the English county elections, the results of which will be announced on Friday. And the party will do even worse in the European elections, the results of which will be announced next Sunday night. Brown will therefore survive as Prime Minister for the time being.
The rule is that, if the media set politicians a hurdle, they will clear it. What trips them up or brings them down is the hurdle that was not advertised and endlessly discussed in advance. Thus Margaret Thatcher was not brought down by the local elections in May 1990. The results were dire for the Conservatives but Kenneth Baker, the party chairman, forewarned by media speculation, was able to sell atypical Tory gains in Wandsworth and Westminster in London as a vindication not just of Thatcher but of her most unpopular policy, the poll tax. No, she was brought down by the unexpected resignation of Geoffrey Howe, and by his even more unexpected savage resignation speech 12 days later, which prompted Michael Heseltine's leadership challenge.
And Tony Blair was not brought down by the local elections in May 2006. The results were bad for the Government, but Blair was able to move the media story on by sacking Charles Clarke as Home Secretary in a brutal reshuffle the next day. What brought him down was an unexpected convulsion of the Parliamentary Labour Party over that summer, because of his refusal to condemn the Israeli invasion of Lebanon, which came to a head with an unexpected round-robin letter signed by a junior minister, several unpaid bag carriers and a handful of MPs.
In between Thatcher and Blair, we had the unlikely example of John Major, who managed to avoid being ousted by his own party but whose survival carries the same lesson. His demise was predicted several times. The struggle to ratify the Maastricht Treaty was erected as a great hurdle that could have brought him down; various local elections were trailed as the moment when Kenneth Clarke or Heseltine or, later, Michael Portillo might strike. At one point, Clarke's succession was so certain that not one but two biographies of "the next prime minister" were published. But it never happened. Clarke refused to temper his pro-Europeanism, and Major's "back me or sack me" self-inflicted leadership election in 1995 was a desperate and successful device to scotch the plots. In fact, the closest he came to falling was early on, after the unexpected shock of the collapse of his ERM policy in 1992, when he told Norman Fowler, then party chairman, that he was thinking of stepping down.
So it almost does not matter how bad the elections are on Thursday for Labour. Records will be broken. Professor Anthony King will be on television declaring that they are the worst results for a governing party since Charles I lost the Battle of Naseby. Governing party robots will be on television to explain why they are not as bad as they seem. They will be, in the words of 1066 and All That, right but repulsive. Labour will probably lose control of all four of its remaining county councils, but the last elections for those councils were held on the same day as the general election, so the comparison is not a fair one.
Equally, Labour's share of the vote in the European elections will probably be a record low, but the Conservative share is likely to be pretty low too, and it is obvious that, more than ever before, people will use the vote as a protest. In this case, the protest is unusually passionate, driven by the fury over MPs' expenses. Labour is plainly suffering most, as the governing party, but the mood is, if not a plague on all your houses, then a pestilence, rain of frogs and death to the first-born on all your houses. We are not in a situation where David Cameron is widely regarded as the fresh-faced bringer of hope, optimism and renewal.
That gives Brown the space he needs to hold on. He has to have the reshuffle power in reserve, at least, in case he suspects that his Cabinet colleagues are coming for him and needs to move first. If Brown is like previous prime ministers, he will be just as worried about surviving the next 10 days as some of the commentary suggests he should be. But if he remembers his training as a historian, he should keep calm and listen to the advice of his Chancellor. "Too early to panic," Alistair Darling told Chris Mullin, 10 days before the invasion of Iraq. "The Labour Party always likes to get its panic in early."
The historian in Brown should tell him that the forces ranged against him are not yet lined up to exert maximum pressure. One factor is the "plague on all your houses" mood. It means that it is not obvious enough that deposing Brown and replacing him with Alan Johnson or David Miliband would help Labour. I think the mood is graded, that public hostility is directed at all MPs, the Government and the Prime Minister in reverse order of intensity. I am convinced that Labour would be less unpopular if there were a change of prime minister, but that is not a universal view. Nor are the alternative Labour prime ministers so charismatic and exceptional that their advance is irresistible. No one has written two biographies of the Health Secretary – although the material is certainly compelling enough.
But, above all, what will keep Brown in No 10 for the moment is that Labour MPs do not want an early general election. They do not want to risk cutting short their pensionable employment by nine months, and they certainly do not want to fight an election in the current atmosphere of rage. Of course, if Brown were deposed next weekend, his successor could refuse to go to the country in the autumn. But that would destroy most of the advantage that the party would gain by changing leader. That would work only as a response to the democratic demands of the times. But by September it will be a very different story. Then, a new leader could promise an early election in the spring. Then, Brown should look out for the unexpected.
John Rentoul's blog is at www.independent.co.uk/jrentoul