Just when things were beginning to look a little bleak for electoral reformers, what with opinion polls indicating a loss of enthusiasm for changing the voting system, relief is at hand. It comes from those who want to cling to the status quo. The NO2AV outfit has unveiled the "big names" who will spearhead the campaign to retain first past the post. Prominent among them is Margaret Beckett. That ex-minister's most memorable recent contribution to British politics was to incite a near riot by the Question Time audience to whom she tried to explain away the parliamentary expenses scandal.

Standing out among the no men is John Prescott, the former deputy prime minister whose offences against good taste and decency are too numerous to list. Over the last decade or so, it has been a reasonable rule of thumb that any cause he champions is a lost cause. Regional assemblies, Gordon Brown, the maintenance of dignity in high public office: none has survived close association with John Prescott.

I make it sound personal because this referendum campaign is going to be intensely so.

You may have thought that an argument about voting systems would be a bit dry, more academic seminar than political mud wrestling. There will be an anoraky aspect to the campaigning between now and the referendum next May.

The ideal electoral system produces governments that are perfectly representative, immaculately accountable and impeccably effective. That ideal electoral system does not exist. All methods involve compromise between these competing aims. That means limitless opportunities for the two sides to wrangle the rival attributes of the alternative vote and the status quo. Proponents of change will contend that first past the post awards parliamentary seats in a way which is wildly out of proportion with votes cast and that weakness has become so pronounced in recent years that MPs can now get elected with the support of fewer than three out of 10 voters. (They will be right.) Opponents of reform will say that AV can also distort the will of the electorate. (They will be right too.) Supporters of the status quo will insist that the current voting system has the great merit of producing reliable parliamentary majorities for single party governments. (That it does – except on those quite frequent occasions when it doesn't, as it didn't at the last election.)

Campaigners for change will say that AV gets rid of tactical voting, forces candidates to seek support from at least half their electorate and gives everyone the chance of their vote counting for something. (That it does.) Those hostile to AV will say that preferential voting privileges the supporters of smaller and fringe parties over mainstream parties. (This may be their best argument.)

A no campaign would normally encourage voters to use a referendum as an opportunity to express disapproval of the government. In this case, they will seek to exploit the current backlash against the Lib Dems by blackening electoral reform as a recipe for permanent Nick Cleggery and endless broken promises excused in the name of coalition. But the overwhelming bulk of the Conservative party is opposed to change: this is the only subject that makes bedfellows, and what strange ones, of John Prescott and John Redwood. So while voting no will hurt the Lib Dems, it will also please the larger, Tory component of the government.

In the context of this referendum, it is not self-evident who represents the establishment. Can that be the government when the coalition is divided about the merits of change? Or is it the Westminster system more broadly? Supporters of change will say that a yes vote is the way to shake up a political establishment corrupted by its sense of entitlement and finally exposed in its manifold rottenness by the expenses scandal. When the technical debates are complex and the battle lines are so confused, many voters are likely to take their cue from who is representing which side. The attractiveness, or otherwise, of those fronting the arguments will matter as much, if not more so, as the arguments themselves.

Most of the faces of the NO2AV campaign have next to nothing in common except their constitutional conservatism. And their age. John Prescott is 72. His fellow "big beasts" are also long in the sabre tooth: Ken Clarke (70), Margaret Beckett (67), David Blunkett (63) and John Reid (also 63). Only in this company could Charlie Falconer (just turned 59) feel young. William Hague (49) is the only heavy hitter associated with the no lobby who has not reached his half century. I draw this to your attention not to be ageist, but because it tells us that they are coming from another age. Most of the politicians fronting the no campaign grew up in the 1940s and 1950s when Britain had a two-party system for which first past the post was defensible. The relatively youthful William Hague is the exception who proves the rule. The foreign secretary has often said that he'd have been much happier as a politician had he been born a century earlier. The world to which they yearn to return is one in which politics was a two-tribe affair. The voters knew their place. That place was to make a simple binary choice between the blues and the reds.

Hostility to reform among some Labour tribalists has certainly been swollen by their bitterness that the Lib Dems entered the coalition with the Tories. But among many of those Labour cave-dwellers, antipathy towards Liberals long predates the formation of the coalition. Indeed, they are partly to blame for it. Labour club-draggers thwarted Tony Blair when he attempted to do a deal with the Lib Dems from a position of Labour strength. John Prescott has always had a visceral loathing for the third party. He threatened resignation when Mr Blair toyed with bringing Paddy Ashdown into the cabinet during New Labour's first term.

The former deputy prime minister is a hater of not just Liberals, but anyone who does not share his jurassic conception of politics. "Collaborator" was the word he used to describe his former cabinet colleague, John Hutton, as if doing a report on pensions for the coalition was the equivalent of working for the Nazis. John Reid and David Blunkett both had pungent relations with John Prescott when the three sat in cabinet together. What they share with him is that head-banging tribalism. In the febrile days of bargaining after the last election, the slim chance of forming a Lab-Lib coalition was made even smaller when the very idea was publicly scorned by Messrs Reid and Blunkett.

Tory campaigners against reform are in a more subtle position. Their cohabitation with the Lib Dems means that Ken Clarke and William Hague now have to be polite, at least in public, about Liberals. But whatever else divides those two Tories, they are also of a tribal disposition.

In Gilbert and Sullivan's Iolanthe, it is sung:

I often think it's comical

How nature always does contrive

That every boy and every gal

That's born into the world alive

Is either a little Liberal

Or else a little Conservative!





Substitute Liberal with Labour and you capture the tribalist view of how politics ought to be.

They used to be right. At the 1951 election, more than 96% of the vote was scooped by Labour and the Tories. Only a tiny minority of voters did not associate with either the red tribe or the blue one. By the two elections of 1974, a quarter of the voters were refusing to make a cross for either Labour or the Tories. The decline of class-based identification with the big two has been accompanied by diminishing respect for the duopoly that dominated British politics for decades. At the most recent election, more than a third of voters rejected both blue and red – and more than a third of the total electorate declined to vote for anyone at all.

The May result was Labour's second worst at a general election since 1918 while David Cameron moved into Number 10 with a smaller proportion of support from the electorate than any previous Conservative prime minister. This was not a surprise one-off. It was the culmination of a decades-long movement against the two bigger parties.

The alternative vote is not a perfect adjustment to this transformation, but it does at least recognise that, for millions of voters, their first choice is neither Conservative nor Labour. AV also has the merit of tending to reward politicians who try to reach out to as many of their constituents as possible. It better aligns how we vote with how most of us now think about politics. A declining minority of people identify wholly with one party. For the majority, any choice is a compromise, there are more colours in the rainbow than just red and blue, and cave-dwelling tribesmen belong in TV documentaries not modern British politics.

John Prescott and co are the elders of lost tribes howling to preserve a world that is already gone.