There is not a politician in the country who won't tell you they want to improve politics. But as the conduct of the current referendum on adopting the alternative vote shows, judge them by their actions, not their words.

I will be voting yes because I believe that changing to AV will substantially improve our democracy.

I disagree with those advocating sticking to the current first-past-the-post system, but respect their right to their point of view.

What I am perplexed and deeply disturbed by is that those running the no campaign haven't once put forward a positive case for the current system and instead have spent their time lying about AV.

I have seen principle-free machine politics in action many times and it is never a pretty sight. But this time really is different.

To have Baroness Warsi stand on the site of race riots in the 1930s and say that a yes vote will help the BNP is as tawdry as it is indefensible. The BNP are campaigning for a no vote. Such extremist parties as have, God help us, been elected in Britain, were elected through FPTP. As a host of independent commentators have argued, AV will diminish their chances, not increase them.

These cynical smears and scaremongering show not only the bankruptcy of the no campaign's arguments but also how low is the level of its regard for the intelligence the public.

The strategy is clear. Throw as much mud as you can, don't let the issue be discussed openly and frighten the public over the next three weeks into voting to preserve the power the present FPTP system has given you.

This strategy stinks of the same odour which has surrounded our politics recently.

For the chancellor of the exchequer – the chancellor of the exchequer – to claim that there is something "dodgy" about the Electoral Reform Society donating cash to a campaign in favour of electoral reform is bizarre.

Worse, for him to casually toss out slurs against a British company – Electoral Reform Services – which has widespread international respect for its impartiality in the conduct of elections and which even the Conservative party get to run their elections, is desperate.

And all of this is done by the no camp while they refuse fully to disclose their own donors!

In one sense, though, George Osborne makes the case for change for us. He graphically shows why we need to change our politics. Why we need to clean it up. Why the voting public deserve something better.

In the 1950s more than 90% of us voted either Labour or Tory. The vast majority of MPs were elected with more than 50% of the vote in their constituencies.

Now that total is down to just 65%. Even when you add in my party, the three big UK parties combined achieved their lowest share of the vote ever in the last general election. One in 10 of us now vote for parties outside the big three.

But the system doesn't reflect the change in people's voting preferences. Now fewer than a third of MPs are elected with a majority of the votes in their constituencies. Some get in on fewer than three out of 10 votes cast.

Most of us are now represented by an MP that most of us voted against.

What is the no campaign's answer to that analysis? They don't have one.

Which is why they have to resort to smears, deliberate misrepresentations and sometimes even downright lies. In so doing they diminish their arguments, insult rational debate and provide the best example of why it is time to change things for good.

At the start of this campaign I believed a yes vote would mean we had the chance to make a closer connection between politicians and people and begin a journey of renewal for our sadly tarnished politics. I still believe that.

But having seen the way those who want us to vote no on 5 May are making their argument, I realise that this referendum is about much more than just a voting system.

It is about giving politics in Britain something better for the future than we have seen in the recent past – and that we now see so graphically in the way the no campaign is making its case.

They have given us a perfect example of why things have to change. Of how our politics will remain if this vote is lost. Of why we need a new voting system, which puts more power into the hands of the voters and takes it away from this old style of old machine politics, which demeans us and our politics alike.