In a month’s time we will know the result — will the British people have voted to modernise our electoral system? The next three and a bit weeks will see some frantic campaigning in the first national referendum in a generation.

Tim Farron is leading the charge for the Lib Dems, as he described here on Lib Dem Voice yesterday. And today Nick Clegg, who as deputy prime minister steered through the legislation to give the public their say, will deliver a speech on the merits of the ‘alternative vote’ in London. You can read the full text below. The BBC report of Nick’s speech can be found here.

UPDATE: You can watch Nick Clegg’s speech here.

It is sometimes claimed that people are apathetic about politics. I think that is completely wrong. People are hungry for change. They just feel powerless to make it happen. Our political system is broken. The understandable anger caused by the expenses scandals has not gone away. And without change, why should it?

We cannot fix everything overnight. But there are things we can do to clean up politics, starting with the way we elect MPs. First Past The Post is out of date and at the heart of so many of the reasons people are disillusioned with politics. It means general elections are decided by a handful of votes in marginal seats. It guarantees jobs for life for hundreds of MPs. It fosters the complacency that led to MPs abusing their expenses. It leaves millions of voters living in parliamentary seats where they know their vote will not make the slightest bit of difference. It leads to elections where more people choose not to vote than voted for the winning party – as we saw in 2005. You deserve better. Britain deserves better.

And AV is a very British reform; a perfect example of the British genius for constitutional evolution, rather than revolution. Think about the many steps we took towards full suffrage, including in 1832, 1867, 1884, 1918 and 1928. The British way has always been reform by instalments.

The Liberal Democrats are of course a party of reform, so it is no surprise that we are vigorously supporting a yes vote in the AV referendum. But no party can claim a monopoly on reform. Benjamin Disraeli was the architect of the 1867 reform. It was Lloyd George, at the head of a coalition government, that delivered votes for women in 1918. The Conservative government under Stanley Baldwin who finally legislated for electoral equality between the sexes, 83 years ago. And the Labour Government of Harold Wilson who lowered the voting age to 18.

There are, and always have been, reformers and conservatives – small ‘c’ conservatives, – from across the political spectrum. So I am delighted that the reformers in the Labour Party, including Ed Miliband, are backing fairer votes. Especially as there are plenty of Labour conservatives, the John Prescotts, Margaret Becketts and John Reids, clinging to the status quo. And I am grateful that there are at least some members of the Conservative Party including a London Assembly member, Andrew Boff, who are carrying Disraeli’s mantle of reform, and backing the very British reform that is AV. That is why the politicians engaged in this argument, on both sides, need to argue their case with passion, but also with a good dose of humility.

This is not about us, or even about our parties. It is about the voters choosing the way they choose their MPs. Long after the names of Ed Miliband, David Cameron and Nick Clegg have faded in the memory, a new and better voting system will be in place. This is not a battle between left and right, between particular politicians, or between one party and another. This is a battle between reformers and conservatives. This struggle usually follows a regular pattern:

The reformers propose a reasonable step towards greater representation or fairness in our political system. The conservatives defend the status quo, usually having come to terms with the last instalment of reform, but warning of disaster if another step is taken. The conservatives try to preserve in aspic whatever system currently exists. The conservative tactic at moments of reform is to paint an apocalyptic picture of the future in the event of change.

So Thomas Carlyle lamented that the 1867 reform meant ‘the end of our dear old England’ while Lord Derby described it as a ‘great leap in the dark’. There are more recent examples, too. In my lifetime in fact.

The decision to lower the voting age from 21 to 18 in 1969 was described by some in the House of Lords as a ‘rash’ move – on the grounds that 18 year-olds should not be seen as mature enough to vote, or indeed to marry without parental consent.

And today the No campaign is making the bizarre claim that AV will lead to BNP victory. Even Nick Griffin knows this is nonsense. That’s why he’s campaigning for a No vote. Nick Griffin knows that AV will make it harder for extremist parties to win because they cannot get the support of a majority of their constituents. Nick Griffin knows that it is First Past the Post that means parties like the BNP stand a chance of being elected with a fraction of the vote. That’s why the No campaign is backed by fascists and extremists. If you want to defeat the BNP, vote Yes.

Time and time again, the conservative doomsayers were proved wrong. The same will be true of AV. The world will not stop turning on its axis when voters write ‘1-2-3’ rather than an X on their ballot papers. I am certain that in years to come, the arguments being deployed against AV will seem as nonsensical as the ones that were used against allowing women the vote nearly 100 years ago and 18-year-olds the vote 42 years ago.

Moving from First Past The Post to AV is a similar reform to the reduction of the voting age, in that it simply brings our system up to date. By 1969, it simply no longer made sense to say that 20 year-olds were not grown-up enough to vote. And in 2011 it no longer makes sense to stick with First Past The Post. The era of two party politics is over. In 1951, 97% of the population voted for either Labour or the Conservatives. In 2010 less that two thirds voted for them. In 2011, in every aspect of their lives, people want more choice. Why should politics be any different?

It is common knowledge that David Cameron and I disagree about this. Yet it is a form of AV that the Conservatives used in his leadership election. The Tories also use it to select their candidates. I find it astonishing that the Conservatives say AV is good enough for them but it is not good enough for the rest of the country.

Look at who is on each side of the argument. On the Yes campaign we have the Liberal Democrats, Ed Miliband and Labour party supporters, the Green Party, UKIP, Plaid Cymru, the SNP, Friends of the Earth, Colin Firth, Eddie Izzard and Helena Bonham Carter. On the No side of the argument are the BNP, the Communists, the Conservative Party, John Prescott, John Reid and Norman Tebbit. Whose company would you rather be in?

AV is nothing more – and nothing less – than an update for democracy. Politics has to evolve as society changes. Trying to insulate politics from progress is a mistake. As Roy Jenkins said: “‘Everybody change but us’ is never a good slogan”.

And of course London, like Scotland and Wales, understand this better than most. The Mayor of London is elected by a form of AV, and members of the London Assembly are elected by a fairer system too. And those elections work fine. Londoners know that it is a fairer system that gives them a stronger voice. And the Mayor a stronger mandate. Every voter and every MP should have that same mandate.

People want their voices to be heard. And they also want MPs to account for themselves better. The expenses scandals highlighted one of the main weaknesses of First Past The Post – the complacency that can be bred by the existence of safe seats where MPs effectively have jobs for life. How else do you explain the behaviour of a London MP – now an ex-MP – like Dawn Butler. Claiming nearly £23,000 a year so that she can have two homes: One at either end of the Jubilee Line?

There was a clear link between how safe an MP’s seat was and how likely they were to abuse the system. These seats are the modern equivalent of the old rotten boroughs. The places where MPs don’t have to work for your vote; where they can be elected with the support of a fraction of the electorate. In modern, diverse 21st century Britain, that is not good enough.

The votes of Londoners have the potential to make a real difference to the result this May. Some say that turnout might be lower in London because there are not any other elections. It is your job to prove them wrong. As the crowd that came to the Evening Standard hosted debate earlier this week showed plenty of people across London care, and care passionately. And they are right to. Because this referendum really matters.

So if everybody in this room goes out and does their bit to get the Yes vote across London it will make a huge difference. And it could be the difference between winning and losing this crucial vote.

The Alternative Vote is a small change that makes a big difference. It keeps what people like about the current system, like constituency MPs. It simply puts people, rather than politicians, in charge. It means more voices being heard. It makes MPs work harder for your vote. And helps end the scandal of safe seats for life.

In just under a month’s time, I hope and believe that the British people will have voted for the very British reform of AV. So we have fewer than four weeks left to get our message across: If you want MPs to work harder for your vote, vote yes. If you want politicians to listen to whole country, not just swing voters in marginal seats: vote yes. And to put it at its simplest: If you want more duckhouses, vote no. If you want more democracy, vote yes.

Change is coming. You can be a part of it. But we need to get out there and spread the message: Yes to cleaning up politics. Yes to putting power back in people’s hands. Yes to fairer votes.