This week, Ukip announced its firm, but fair, immigration policy at the Emmanuel Centre in the heart of London. I was delighted to be flanked on stage by many of our candidates, some of them immigrants, or first or second generation immigrants themselves, who know that we have the most ethical and sustainable policy of all the parties.

This is because Ukip realises that for decades Britain’s net migration numbers hovered around 30,000 a year. That is sustainable for our country – though even those figures sparked fierce debate in the United Kingdom.

And yet, under this Conservative government, which promised to reduce net migration to the “tens of thousands” – we now have 300,000 people, net, coming into the country every year. This is up from 196,000 under Labour – who opened Britain’s borders to new EU citizens – in 2009.

So when Ukip talks about immigration control – especially the Australian-style points system we’ve proposed – the national media goes into a frenzy. Let me give you an example. It’s apparent to anyone who’s willing to be honest about it, that nine million more people in this country – through natural growth as well as via immigration over the past 20 years – has added to the strain on our National Health Service, on our school places, and on our housing situation.

And yet, when I say that our Australian-style points system would prohibit those with long-term diseases coming to this country, there’s uproar. Well, just like Australia does, a British immigration system would look at the quality of the candidates who wish to come into the country. For instance, how old are they? What skills do they have? What languages do they speak? And yes, do they have a long-term ailment that would require them to use the resources of the NHS upon entry, and at great cost?

You’d think all these things were normal things to take into consideration. After all, cancer and HIV treatments aren’t cheap, and it isn’t fair or ethical to expect the British taxpayer, who has paid into the system their whole lives, to fund the treatment for a migrant who has just arrived here and hasn’t yet made the requisite contributions.

That’s why we’d ensure that people who came to the UK on work visas had health insurance, too. It’s a policy that is moral, as well as one that keeps the interests of the British public at heart. And that’s not to say that HIV-positive people are going to be turned around at the border. It is to say that the points system will weigh against people will long-term illness, so as not to cause further strain on our NHS.

I know it’s not necessarily the most popular thing to say, nor is it the nicest thing to have to enforce. But if we truly believe in a sustainable solution to the problems caused by immigration – if we want people to start feeling that immigration is a net positive, not negative thing – then we have to take firm but fair decisions.

Cameron has lost his nerve over TV debates

So David Cameron has this week shown his true colours; yellow. I mean even the Liberal Democrat leader had the gumption to debate against me ahead of the European elections. But Mr Cameron is frit. And he’s sending the Tory punchbag Grant Shapps onto television to take beatings from the other parties and the national media over the issue.

Remember, once upon a time, Mr Cameron was a big proponent of televised leaders’ debates. Then he began to look less keen. It might be because if he was held to account by me on the national stage, he knows he’d have to answer for his record in government. He knows he’d have to look at the list of policies he announced in 2010, when he said, “If I don’t deliver, kick me out” – and be shown up to have been completely ineffective.

It might be that he’d have to admit to a lost five years in government, during which he has doubled Labour’s 13-year debt in less than half the time, and then used the proceeds of that borrowing to Astroturf economic growth. Or maybe it’s because he promised to bring net migration down to the tens of thousands, and yet under the Tories, it’s now the highest it’s been in a decade.

Whatever the reasons, let me say this: Mr Cameron, if you are a real leader you’ll debate against me, Mr Miliband, and Mr Clegg in a four-way debate. And Mr Miliband, if Mr Cameron doesn’t want to go against you one-on-one… I will. How about that?