LEADING Brexit proponent Boris Johnson has called for a tough, “Australian-style” system for handling asylum seekers if Britons vote to leave the European Union at a referendum on June 23.

With fellow Brexit backers Michael Gove and Priti Patel, Johnson released a statement calling for a “tough Australian-style points system” to handle refugee numbers to be introduced by 2020.

“The automatic right of all EU citizens to come and live and work in the UK will end, as will EU control over vital aspects of our social security system,” the trio said in a written statement.

“If we implement these principles, for the first time in a generation it will be possible for politicians to keep their promises on immigration.”

Their statement — a clear sign of defiance against UK Prime Minister David Cameron, who wants the UK to stay in the EU — comes as two new opinion polls show the Brexit campaign is gaining ground.

The findings surprised many commentators ahead of the June 23 referendum because most recent polls have given the “Remain” camp a narrow lead.

One of the ICM polls for the Guardian newspaper was conducted online — where pollsters typically believe more voters say they want to leave the EU — and one was conducted by telephone.

The online vote showed 47 per cent would like to leave while 44 per cent backed Mr Cameron’s “Remain” campaign. A further nine per cent were undecided.

In the telephone poll, 45 per cent said they favoured leaving while 42 per cent said they backed remaining. A total of 13 per cent did not know.

It was only the third phone poll in the campaign to put the “Leave” camp ahead.

“Our poll rather unhinges a few accepted orthodoxies,” ICM’s director, Martin Boon, told the Guardian.

“It is only one poll, but in a rather unexpected reverse of polling assumptions so far, both our phone poll and our online poll are consistent”.

Once undecideds were excluded, both new polls gave 52 per cent support for Brexit compared to 48 per cent for “Remain”.

In Tuesday’s UK Daily Telegraph, Australian political operative Lynton Crosby — who was Mr Cameron’s campaign strategist at last year’s general election — said an “increasing focus on lack of control over immigration” was key to what he said was a shifting mood.

Mr Johnson last week seized on figures which put net migration into Britain at 333,000 last year to argue that it should pull out of the EU.