The "No" campaign holds its formal launch. In between winning the most glamorous awards in the Western world, Colin Firth and Helena Bonham Carter sign up to the "Yes" campaign. The Lords battle over several long nights with a rare passion in an attempt to make their mark on when and what form the referendum takes. Yet still the looming vote on electoral reform seems marginal.

With the Coalition unleashing other reforms and deep spending cuts, the sense of ghostly distance is understandable, but it is also misplaced. The heightened passion in the Lords is closer to matching the scale of the impending drama. The referendum will change British politics more vividly than any of the other more immediately dramatic themes.

So far, fleeting speculation on its impact is based almost entirely on the assumption that the "No" campaign will win. During last year's impressively calm Liberal Democrat annual conference in Liverpool, there was a lot of talk about how much more tempestuous the party's gathering would be in 12 months' time, "once" the referendum had been lost. Ever since, the apocalyptic questions are posed almost exclusively in relation to Nick Clegg and his party.

Will the Liberal Democrats stay in the Coalition for a full term if they are slaughtered in the May local elections and lose the referendum? Will Clegg's leadership be called into question? What can David Cameron do to make life palatable for the Lib Dems if they are denied their eternal dream of electoral reform?

The focus on the Liberal Democrats, combined with the false sense of distance, obscures a much more interesting and suddenly realistic question: what if the "Yes" campaign wins? Almost unnoticed polls suggest that such a result is possible. For what it is worth, I have changed my mind and would place quite a lot of money on a majority supporting change, having worked on the assumption for months that the "Yes" campaign was doomed.

I might even go and place a bet. The last time I did so was to put money on Gordon Brown not calling an early election in 2007. I made a fortune, enough money to fund my Oyster Card for at least a fortnight. The earlier gamble springs to mind because my reasoning is similar now. I could not see Brown taking the risk of an early poll when he had spent most of his life hoping to be prime minister, had made no plans for an early election and the polls were turning. Similarly, I cannot see voters rejecting the chance for "change" in a referendum when the anti-politics mood is so strong.

Most of the "Yes" and "No" votes will not be based on an analysis of the alternative vote. The last national referendum in 1975, on our continued membership in Europe, was not determined by a close reading of Britain's obligations and benefits as a member of the Common Market.

This time, I suspect those who bother to vote, still in a state of anger about MPs' expenses and now alarmed by the cuts, will take the chance to bring about what will be billed as a "new politics". Such a move will also place them on the more fashionable side of the argument. Would you prefer to be with Helena Bonham Carter, Colin Firth and Stephen Fry, or Margaret Beckett, John Prescott and Simon Heffer?

This is no comment on the many merits of the latter trio. Personally, I am not a supporter of referendums precisely because votes are cast for the wrong reasons, which have nothing to do with the subject, and I would be as thrilled to spend an hour with Simon Heffer as I would with Colin Firth. But we are where we are, as powerless leaders often have cause to reflect, and it seems to me that the "Yes" campaign has all the populist arguments and cooler supporters.

At the very least, it is worth pausing to reflect on this alternative scenario, one in which the Liberal Democrats become the happier wing of the Coalition, one immediate consequence of a "Yes" victory. However badly the Liberal Democrats fare in the local elections, a "Yes" vote would give the junior partner fresh purpose. Instead, the crisis would be within parts of the Conservative Party. As Clegg would be the first to acknowledge, Cameron and Osborne offered him a referendum on the assumption he would lose it.

Some restive Conservative MPs would fume if they lost a first-past-the-post voting system that delivered majority Tory governments like clockwork for much of the last century, and could easily do so again. Managing the Conservative Party would become as much of a priority for Cameron, who would have been on the "losing" side, as keeping the Coalition moving forward has been until now.

Less important, but not without significance, Lib Dems would have been campaigning on the same side as the Labour leader, Ed Miliband, in a victorious campaign. Central to Miliband's strategy is a closer relationship with like-minded figures from the Lib Dems and, indeed, the Green Party. His still vague intent would have acquired some shape, although a significant section of the Labour Party would have been campaigning for a "No" vote.

Of more immediate significance, MPs from all parties would be suddenly functioning in a context in which, to slightly rephrase Donald Rumsfeld, their unknown futures become even more unknown. Already this is the most rebellious House of Commons since 1945. If there is a "Yes" vote, MPs would face a new voting system and revised boundaries at the next election while functioning in the still novel context of coalition government. Such a prospect will be unnerving in an already nervy hung parliament. MPs will become even more difficult to control.

Perhaps I will be proved wrong. There was, and still is, good cause for the widely held assumption that the "No" vote will win. In referendums voters tend to support the status quo. Most of the still highly influential newspapers oppose a change. The Conservatives and quite a lot of Labour are against. Even some Labour supporters who are in favour of the alternative vote wonder about giving Clegg a boost at a point when defeat could throw him and his party into turmoil.

More fundamentally, it is possible that, for a time at least, Britain is returning at a national level to a battle between two parties, a conflict that works well under the existing first-past-the-post.

There is also the issue of the immediate context in which the referendum is being held. Under the guise of improving democracy, the Bill that clears the way for the plebiscite is crudely self-interested. The Lib Dems get their referendum and the Conservatives get the boundary changes to seats in ways that are likely to be beneficial to them. Allies of Clegg insist that the agreement was not made in a spirit of mutual co-operation but the precise opposite. The Tories were convinced he would lose the referendum and he does not believe that the boundary changes will benefit David Cameron. Whatever its origins, the referendum has not descended from a pure sky.

But no referendum arises from pure motives. The previous one in 1975 was offered by Harold Wilson to prevent his party from splitting in two. Britain went to the polls on a sunny day in June to save the Labour Party. A referendum on electoral reform was only ever going to happen when the Lib Dems held the balance of power. They hold the balance. The referendum is happening. Nothing will ever be the same again

s.richards@independent.co.uk

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