GETTY David Cameron wrote a Tory manifesto which promised an Australian-style points system

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The Prime Minister was behind a Tory pledge to introduce a strict immigration system in the UK ten years ago, it has emerged. The explosive revelations threaten to make a mockery of his claims that such a points-based system – proposed by leading Brexit campaigners – would "trash the economy". The Conservative Party's 2005 election manifesto pledged to introduce a "points-based system similar to the one used in Australia" – which only grants economic migrants a visa if they pass a points test based on their qualifications and work experience – to "give priority to people with the skills Britain needs".

GETTY David Cameron pictured in 2005 – when he backed an Australian-style system

In a chilling echo of the Government's lacklustre response current migration crisis, it reads: "Our out-of-control immigration system encourages people smugglers and penalises genuine refugees. Remain campaigner Cameron was responsible for producing the policy document – but now says the system is "unworkable". His Europhile ally George Osborne, the Chancellor, also attacked the policy as "fantasy politics". But a briefing sent to Tory candidates in 2005 said the party would "consult businesses every year to ensure that the right balance – involving the right number and type of immigrants – is struck by the points system".

Cameron's shocking U-turn was flagged up by the Conservative Party's official historian, Lord Lexden, in a withering letter to the Daily Telegraph. Challenging the Prime Minister, the top academic asked: "Why is that policy now wrong?" Brexit heavyweights including Boris Johnson and Michael Gove have pledged to allow entry to the UK based on skills only if Britons vote to quit the Brussels club on June 23rd.

GETTY Leave campaigners including Boris Johnson have pledged to introduce an Australian-style system

GETTY Michael Gove also backs the pledge

An official Vote Leave statement from the former London Mayor and Justice Secretary as well as Employment Minister Priti Patel and senior Labour MP Gisela Stuart said: "To gain the right to work, economic migrants will have to be suitable for the job in question. "For relevant jobs, we will be able to ensure that all those who come have the ability to speak good English.” The campaigners – who are surging in the polls – say their plans would slash the UK's current net migration count of 330,000 people a year.

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