$130,000 prize to help UK leave the EU

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A prize of 100,000 euros ($130,000) will be given to the best plan for the U.K. to leave the European Union, a free market think tank announced on Tuesday.

The Institute for Economic Affairs (IEA) is holding the "Blueprint for Britain" competition which aims to see how the U.K. could hypothetically fulfill an orderly exit from the EU. The plan will also need to map out how the country might fit into the new geopolitical and economic landscape that might follow.

A referendum bill which could lead to allowing Britons to vote on whether they want to stay in the EU has so far passed the first stage of parliamentary discussions. The U.K. has been part of the EU since 1973.

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The liberal think tank, which has offered the cash prize in euros rather than pounds, says submissions around 2,000 words are invited from individuals, groups of individuals, academia and corporate bodies such as consultancy firms, law firms, accounting firms, think tanks and investment banks.

"An 'out' vote in a British referendum would be a major historic geopolitical and economic event, perhaps even comparable with the fall of the Berlin Wall and the subsequent collapse of the Soviet Union and reunification of Germany," the IEA said in a press release.

"It is time, therefore, that the U.K. explores the process of withdrawal and its economic and political consequences."

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Submissions should focus on how laws are changed after a possible "Brixit" and how global trade is renegotiated, it said. The deadline for entries is September 16 and the judging panel includes Nigel Lawson, Conservative finance minister during the 1980s - who has previously called for a U.K. exit, historian David Starkey, numerous figures from London's financial world including Roger Bootle, founder of Capital Economics, and a Labour opposition politician.

The U.K.'s membership of the EU has been a hot topic in the country in recent months with the Conservative Party - which currently heads a coalition government - losing ground to a eurosceptic U.K. Independence Party in local elections. In the latest poll by research firm IPSOS Mori in November, 48 percent of people asked said they would leave the EU immediately, 44 percent said they would stay in.

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The current parliamentary bill - which proposes a vote by 2017 - was voted through its first stage unanimously on July 6, but opposition Labour lawmakers and Liberal Democrats - the Conservative's junior coalition partner - boycotted the vote en masse. Deputy Prime Minister and Liberal Democrat leader Nick Clegg dubbed the bill a "complete stunt" when speaking to the BBC.

However Bootle said that with high public support for an EU-exit, and a national election looming in 2015, both opposition parties would be forced to offer something similar to the Conservative's referendum promise. He told CNBC it was important the British public faced the decision about EU membership "in the best-informed way", adding that this was the rationale behind the IEA's competition.

Bootle said one alternative to a complete EU-exit was the U.K. remaining part of the single market, which guarantees freedom of movement of goods, services and people within member countries. However, he warned this would fail to assuage the British public's concerns about uncontrolled immigration.

As a so-called "eurosceptic", Bootle said concerns that U.K. trade would plummet if the country left the EU were "complete and utter nonsense". He highlighted that similar concerns had been raised when the U.K. opted not to join the euro zone, and had proved untrue.

Also speaking to CNBC, Alan Clarke, a U.K. and euro zone economist at Scotia Bank, agreed that there would not be a nosedive in U.K. trade if the country left the EU.

"These end-of-the-world doomsday scenarios won't happen," Clarke said.

By CNBC.com's Matt Clinch and Katy Barnato.