David Cameron needs to forge a "minimalist" relationship for the UK with the European Union, a senior Tory MP has argued, warning that the political bloc is "too costly politically and economically".
Brian Binley, member of the Commons business committee, also said the government should calculate the true cost of Britain's membership of the EU should be calculated and publish it before any negotiations with Brussels over reforms ahead of an in/out referendum.
In a pamphlet for the Civitas think-tank, the Northampton South MP said it was important that voters be shown the true numbers, suggesting the calculations should form part of the review of competence already under way across Whitehall departments.
"Led by the Treasury, they should now finally audit the actual costs of each of the treaty sections they have been looking into; and 11 Downing Street should then add up the sums as an adjunct to the final report," he wrote in a joint publication with former parliamentary adviser Lee Rotherham.
"In other words, we need a genuine cost-benefit analysis and we need it quickly."
Setting out his own future preference, he said: "At some point, and we have in all likelihood already passed it, being a full EU member is too costly politically and economically for a country like the UK. We don't need the full gym membership.
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"The cost-effective route is then one of separate association treaties, with current key titles removed. In effect, that takes us to being of the EU but not in the EU, rather like Churchill's way of looking at our relationship with the continent: associated, but not absorbed.
"We simply do not need to be in a treaty association that, like some crazy insurance plan, adds unnecessary costs to the deal we really need.
"We should go minimalist and lift out just the trade sections; and then on top of those aspects, individually add on those bits we actually think cooperation does work for us if we sit together in a room at Brussels working on them.
"Much of that will turn out best done bilaterally with individual member states."
Meanwhile, a row has erupted over the impact of European Union regulations on Britain after a campaign group claimed that nearly two thirds of UK law was either made or influenced by Brussels.
Business for Britain said 64.7% of all laws in force today either originate in the EU or are deemed by the House of Commons library to be EU-influenced.
The figure falls in between estimates made by Ukip leader Nigel Farage and Deputy Prime Minister Nick Clegg in debates between the pair on the EU.
Clegg and Farage argue about the number of laws coming from Brussels
Farage had claimed that 75% of British law is made in Europe, with the Liberal Democrat leader putting the figure at around 7%.
The Business for Britain study claimed that EU regulations accounted for 59.3% of all UK law, while UK laws implementing EU directives accounted for 5.4% of total laws in force in UK.
Matthew Elliott, chief executive of Business for Britain, said: "Access to the Single Market should not come at the cost of having two thirds of our laws being decided by the EU.
"There must be a significant reduction in the amount and scope of EU legislation and powers over certain policy areas should be given back to Parliament so decisions are made far closer to the British people."
However, the Business for New Europe (BNE) coalition of business leaders hit back, saying that looking purely at the volume of regulation ignored the fact that many of the rules are implemented to harmonise regulations across Europe.
BNE chairman Roland Rudd said such harmonisation made it easier for British businesses to export, while being in the EU allowed the UK Government to have some influence over the regulations.
He said: "It is wrong to imply that all laws originating at EU-level are undemocratic or over-burdensome.
"The UK gets a seat at the negotiating table, and most of the time, one EU law gets rid of 28 different national laws across Europe, making it much simpler and easier for businesses to export.
"By counting only the volume of regulation, this report fails to recognise the value that these rules have brought to Britain. The peak of EU regulation was during the creation of the Single Market, which has been hugely positive for British business, described by the Prime Minister as 'the greatest asset we've got... the biggest market in the world'."