Nigel Farage has said David Cameron's attempt to win back powers from the European Union is in tatters and that Britain would have "bigger and better opportunities" if it severs its ties with Brussels in a Brexit.
The prime minister wants to remain in the EU but on new terms that benefit Britain. He has lobbied EU leaders for deals on issues including immigration, the repatriation of powers and trade. But staunch anti-EU Ukip leader Farage believes his plan has failed and leaving the union would be to Britain's benefit.
Speaking on the Andrew Marr Show he said: "The fact that we are discussing this shows you the renegotiation is going nowhere. So rather than us attacking him for his lack of demands he's trying to move the debate, in a sense, to the end-game."
He pointed to countries like Norway - a non EU-member - as an example of how Britain's relationship would work if the referendum returned a "leave" outcome. "We are a country of 65m people, we are the biggest single trading market in the world for the Eurozone. They sell us £50bn-worth of goods every year more than we sell them. If Norway, Iceland and Switzerland can get deals to suit them we can do something far, far better than that."
"We would be getting out of a political union with Europe and re-joining the world... we are the fifth or sixth biggest economy in the world depending on what measure you use and we're actually banned from making our own trade deals with any other part of the world. I want us to have a simple free trade agreement with the EU not to be a member of a political club, not to be subject to the decisions of its courts."
He dismissed comments made by US trade representative Michael Froman that America would not deal with a Britain that was not part of the EU and described them as "scaremongering".
"He's clearly been paid to say that, hasn't he," the Ukip leader said. "This is the big political club gathering around the prime minister who is clearly in desperate trouble with this referendum. This is laughable. America has got a free trade deal with Oman. America has got a free trade deal with Australia. Are you seriously telling me their oldest and closest global ally with whom they do enormous amounts of business...big commercial companies would say don't talk such nonsense. It's an attempt to scaremonger by a paid official."
The Office for National Statistics last week predicted that the UK's population is to swell to 70 million by mid-2027 and, Farage said, lead to worse lives for people living there.
"I've been saying this now for a decade that actually a population rising as rapidly as it is is quite impossible for our primary school system to cope with, impossible for our health services to cope with we already have to build a new house every seven minutes in this country just to cope with current migration levels and it has led to a lack of cohesion and division in our societies.
"Some things are more important than money and the shape and cohesion and happiness of his country matters far more, If another 10m people our quality of life will go down."