Some politicians still don’t get it. Dodgy dossiers and duck islands have shattered our confidence in Britain’s political leadership. But politicians respond not by readdressing themselves to the public at large but by deploying sophisticated campaigning techniques to focus ever more narrowly on a handful of voters in a handful of seats that determine the outcome of elections. Messages are prepared and market-tested and honed to appeal exclusively to Worcester Woman and White Van Man.

Meanwhile, the rest of us are ignored: our concerns are of no concern to an increasingly arrogant and out-of-touch political elite. Little wonder, then, that so many are close to giving up, not just on individuals, but on the whole political process, with potentially disastrous results for our democracy. We cannot go on like this: it is time to take on the politicians, challenge the status quo.

Symbolic of the politicians’ disdain for voters is the refusal, election after election, to countenance a televised leaders’ debate, refusing to open themselves up to scrutiny on what is the main medium of mass communication.

Why is it that voters from Washington to Warsaw, Tel Aviv to Tehran, Moscow to Madrid are able to hear their leaders pit their wits against each other in free and open debate, while here, in the UK, our leaders refuse us that opportunity?

Why, even in Kabul, do aspirant leaders recognise the need to empower voters through the raw red meat of head-to-head debate, yet we are left to feed on the scraps of stage-managed photo opportunities and “spontaneous” questioning from handpicked supporters?

At any election there will always be someone with an interest in stopping a televised debate. My party is winning: why rock the boat? My style doesn’t lend itself to soundbites. The format favours my opponents; they will gang up against me. Boo-hoo.

So the spin doctors tell us we don’t need a televised debate because we already have Prime Minister’s Questions. But once the election campaign begins, the weekly routine ends. Where’s the public accountability in that?

They will tell us a TV debate would be unfair because it includes one party or excludes another. We all know, however, that there are only three parties that contest nearly every seat in the land, and have significant representation in Westminster. They and they alone should be the participants.

Why do the politicians go through such contortions to stop TV debates? Because they understand that studio debates really can transform an election campaign. One unguarded answer can give the lie to a policy fudge or expose a lack of experience otherwise hidden from electors.

At the height of the Cold War, in the 1976 US presidential debate, Gerald Ford embarrassingly insisted that the Soviet Union didn’t dominate Eastern Europe.

Debates can also give an unintended insight into a person’s true thoughts and character. George Bush Sr’s glance at his wristwatch in debate spoke volumes as his rival Bill Clinton replied to an audience member who had asked how the recession had personally affected the two candidates.

And they can enable candidates to address directly accusations against them. Ronald Reagan’s tongue-in-cheek pledge not to use Walter Mondale’s youth and inexperience against him in 1984 silenced those who were arguing Reagan was too old for a second term.

Even once cornered, politicians will make every effort to sanitise any debate by dictating the format, the questions, the audience and the timing. But we have learnt from the expenses outrage. We have heard one too many MPs excuse his or her actions — forget ethics, forget morals — as “within the rules”. We’ve learnt the hard way: the people who play the political game mustn’t also be allowed to set the rules of the game.

So here we are nine months before a crucial general election. Public confidence in politics is at the lowest ebb and something must be done to restore faith in our political system. That is why, today, I have written to Gordon Brown, David Cameron and Nick Clegg, informing them that Sky will be hosting a live debate between them during the election campaign.

This time, all three leaders might be up for it. Mr Cameron has made it very clear that he is in favour. But there can be no backsliding. This time too much is at stake.

We will act with an independent body — there are any number of candidates, from the Hansard Society to the Electoral Commission — to ensure that that there can be no just accusation of partiality.

I understand that some will feel angry to be excluded. We recognise that, and commit ourselves now to hosting separate debates in Scotland and Wales. I know that for some this may not be enough, but I make this prediction: the public will be quick to punish any party that turns to lawyers in a vain attempt to prevent the public having the opportunity to hold its leaders to account.

I also recognise that — however much I might wish it were other — a televisual moment of such importance cannot be “owned” by any one broadcaster. We will, therefore, offer the debate live and unedited to any of our competitors that want to run it. We are ready to sit down with them to discuss the timing and staging: this debate must be about empowering the British people; egos and self-interest must be set aside by all of us.

So there we have it. The UK’s first televised leaders’ debate: no extended negotiations over lighting or rebuttals; no rows about who goes first and who gets to question whom. A date and time will be set. Three chairs provided.

The decision for the politicians is simple: fill them or leave them empty. I give this guarantee: the cameras will be rolling and anyone who doesn’t show up better be ready to explain themselves to the public.

John Ryley is head of Sky News

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