Former London mayor Boris Johnson says a British exit from the European Union would bring Australia and the UK closer together.

Key points: Referendum on whether Britain should stay in the EU to be held on June 23

Referendum on whether Britain should stay in the EU to be held on June 23 Boris Johnson is leading the campaign for a vote to leave the EU

Boris Johnson is leading the campaign for a vote to leave the EU Many economists say Brexit would be an economic disaster for Britain

Mr Johnson, who is the lead campaigner for a "Brexit" at next week's historic referendum, claims it could allow more Australians to get UK visas and boost trade ties between the countries.

"It's a chance for us, in our country, to take back control of all sorts of aspects of our lives including, for instance, immigration policy, which, as you know, at the moment is very heavily skewed towards the European Union, it's very biased," he told 7.30.

His view is at odds with many senior Australian politicians.

Prime Minister Malcolm Turnbull has recently urged Britons to vote to remain in the EU, and Tony Abbott and Bill Shorten have publicly backed the case to Remain.

But Mr Johnson believes Australia’s current political leaders are merely publicly supporting the position of the British Prime Minister.

"I think what happens is you've got a friendly government who's put all their eggs in this particular basket," he said.

"I've listened carefully to what friends have said in Australia and they see the advantages of us taking back control of our immigration system and huge sums of money."

Mr Johnson said Australia would never consider ceding any sovereign powers to an organisation like ASEAN, and urged the 1.3 million British citizens living Down Under to vote Leave.

"I want to ask a question of our Australian friends: would you dream of immersing yourselves into a supranational system where you had judges from heaven knows where sitting on your courts making sure a unified system of law was applied all across Australasia?" he said.

"That's not the way it would work for Australians, it's time for a different system here."

The Leave camp appears to have gained ground in recent weeks by campaigning heavily on immigration.

They argue EU freedom of movement rules give the UK little control over the numbers of unskilled Europeans who come to the country to work and want an Australian style immigration system put in place as soon as possible.

Bad for Britain, Europe and the West: Economist editor

Economists and almost all Western leaders say a Brexit would be very bad for Britain and the West.

Zanny Minton Beddoes says there will be economic consequences if Britain leaves the EU.

As editor in chief of The Economist, Zanny Minton Beddoes is one of the most influential financial journalists in the world.

"In the short-term undoubtedly there would be a very large cost for the British economy and quite possibly for the global economy for the simple reason it would cause enormous uncertainty," she told 7.30.

"Firms don't invest, they don't grow, create jobs, the pound would be hit, asset prices would be hit, I think in the short term undoubtedly there would be costs.

"In the longer term I also think there would be costs because I think that Britain as part of European Union and part of the single biggest market in the world, 500 million consumers, and it is not at all clear that Britain could replicate that access outside the European Union and so I think Britain would be worse off in the long-term too."

Boris Johnson for PM?

Mr Johnson claims the Leave camp is still the underdog at the referendum.

But polls suggest the campaign is tighter then many pundits predicted and the race is seen as a test of the former London mayor's political appeal.

He is now many bookies' favourite to one day take over from current Prime Minister David Cameron.

"As I've constantly said... my chances of being Prime Minister are about as good as being reincarnated as an olive, this is not just something I'm focusing on," Mr Johnson said.

But it is something his party will be looking at closely if Mr Johnson can do what was once considered unlikely and lead Britain out of the European Union.

