The wooing of Nick Clegg

This is a once-in-a-generation opportunity to heal the divide on the centre left. Don't betray us, N

So now we know. Vote Clegg and you won't get Brown. But you might get Cameron. Gordon Brown's bold gamble to quit the Labour leadership, yet stay on in No 10 as Prime Min­ister, transformed the political landscape in a single afternoon. The Prime Minister's decision to stand aside in the interests of a "progressive coalition" helped undermine Tory overtures towards the Liberal Democrats. If it works, it could prove to be a final stroke of genius from a master of the political dark arts (and you may know the answer as you read this). Either way, the Tories and their panicked allies in the press have once again ignored the overarching lesson of the past 13 years: never underestimate Brown. He saw off six Tory shadow chancellors; he may yet see the back of another Tory leader, too.

Brown's plan to stay on in Downing Street has enraged what Tony Blair once called "the forces of conservatism". These include the Conservative Party itself, the City of London, swaths of the media and even sections of the civil service. (A source close to the Prime Minister tells me that civil servants had been so sure of an outright Tory victory that they had already rearranged the furniture in Downing Street and installed new printers and fax machines in preparation for a Cameron occupancy.)

The vitriolic attacks on the Prime Minister from a partisan press corps have been as relentless as they have been inaccurate. The Mail on Sunday gave prominence to a BBC report claiming Brown had issued "a diatribe laced with threats" in a phone call with Nick Clegg - a story denied both publicly and privately by Labour and Lib Dem spokesmen. "It's absolute bollocks," one Downing Street official told me.

Tory attack dogs

Meanwhile, the Sun and the News of the World - Rupert Murdoch's chief attack dogs - hysterically dismissed Brown as a "ranting squatter" in No 10. Attempts to question his legitimacy have foundered, however, as even Andrew Turnbull, the former cabinet secretary who once castigated the Prime Minister for behaving with "Stalinist ruthlessness", has acknowledged that Brown is "entirely within his rights" to stay in office, "and that is exactly what we should expect him to do".

Then there are the broadcasters. The Murdoch-owned Sky News has come under the spotlight after the Brown loyalist Ed Balls described it to me as "deeply partisan" in a pre-election interview. This week's live, on-air spat between Alastair Campbell, Labour's spinner-in-chief, and a red-faced Adam Boulton, Sky's political editor, did not help the channel's cause. But what of the BBC? I have lost track of the number of times its presenters and reporters have echoed Tory positions. Its political editor, Nick Robinson, has hyperventilated at the prospect of Labour, post-Brown, having another "unelected prime minister".

But Britain is governed by a parliamentary, not a presidential, system of government - despite the broadcasters' best efforts to convey the opposite impression during the three leaders' debates. Premiers are not elected by the public. Winston Churchill, Harold Macmillan, Alec Douglas-Home, Jim Callaghan and John Major all arrived in No 10 without the "mandate" of a general election victory.

There is also the BBC's obsession with the supposed instability of a putative coalition government composed of Labour and the Liberal Democrats, and its clamour for a coalition to be formed in days rather than weeks or months. This, even though multiparty coalitions abroad, often painstakingly assembled, have proved remarkably durable, not to mention fiscally responsible.

It is dispiriting to see senior Labour figures echoing this ill-informed babble. "To ally with the Liberals would be madness - and it'd be totally unsustainable," one former cabinet minister told me. Labour tribalists, it seems, are as much members of the "forces of conservatism", currently ranged against the government, as the Tories, the media and the financial markets. They are heading down a dangerous road.

Labour's tribal tendency appears to prefer the purity of opposition to a "back-room" deal with the dreaded Liberal Democrats. But in offering a helping hand to Cameron's Conservatives, these tribalists - who extend from Diane Abbott and Jeremy Corbyn on the left to John Reid and David Blunkett on the right - risk betraying their party's cause far more than any prospective coalition with the Lib Dems might do. There is a principled argument for backing Brown in office. "Tactically, it might be beneficial for the party to go into opposition against a Tory-Lib Dem government," says one Downing Street source. "But it is a real risk for the country to cut spending this year. We don't want to see a double-dip recession which will hurt the poor more than anyone else."

Forces of progress

To borrow once more from Tony Blair's 1999 party conference speech, this is a battle between "the forces of progress and the forces ofconservatism". For now, the cabinet's pluralists - led by an emboldened Brown and quintessentially New Labour figures such as Peter Mandelson and Andrew Adonis, but supported also by one-time tribalists like Balls - are in command.

The pressure is on Clegg. He has to tear up the party's Orange Book, ignore the Tory-inclined David Laws and forget his own past as a member of the Cambridge University Conservative Association. Forty-three per cent of Lib Dem voters described themselves to YouGov as centre left or left, compared to just 9 per cent who described themselves as centre right or right. "Ours," as one Liberal Democrat frontbencher acknowledges, "is a centre-left, not a centre-right party."

This is a once-in-a-generation opportunity to heal the divide on the centre left and reunite two progressive traditions. Don't betray us, Nick.