Britain should trigger a process that would give it back-door independence from the European Union and challenge Brussels to "do its worst", a report recommends.
Amending laws that define the legal relationship with Brussels to enshrine the superiority of the Supreme Court would amount to a "unilateral declaration of independence" without tearing up all EU regulations in one go, according to Civitas.
The right-leaning think-tank insists that France and Germany have flouted EU legislation when it has suited them to little cost.
"Because of their importance to the EU project, nothing was done. We should follow their example and challenge the EU to do its worst," director David Green said
"It is tragic to watch the free people of Britain, who historically led the way in establishing modern freedom and democracy, absent-mindedly give up their powers of self-government.
"What's at stake is far more than our future prosperity. It's our ability to uphold our distinctive contribution to Western civilisation. The huge cost of the EU is undoubtedly a very important question, but even if the cost were zero - for that matter, even if we made a profit - the case for upholding our independence would stand."
He added: "The EU makes occasional concessions to democracy here and there, but the primary thrust of the EU project from the outset has been to centralise power in the hands of rulers who have as free a hand as they can get away with.
"We need to restore parliamentary sovereignty, which means we should restore the authority of the majority of the British people acting through Parliament."
The report, Demise of the Free State: Why British democracy and the EU don't mix, calls for a one-line Bill to be tabled amending the 1972 European Communities Act to declare that UK law is supreme and cannot be over-ruled by Europe.
It says the UK courts would have no choice but to follow the direction of Parliament. Britain would then be able to unpick legislation set by Brussels without having to withdraw from the EU at a stroke.
"We should make explicit the primacy of Parliament by amending the 1972 European Communities Act and declaring our own Supreme Court to be a higher authority than any other court," Green said.
"Henceforward, laws passed by Parliament would be superior to any EU laws. This would amount to a unilateral declaration of independence, but would not imply immediate renegotiation of every law and regulation. We could take our time and go through the numerous unwanted laws one by one."
The report has been backed by JML founder John Mills, one of Labour's biggest donors, who wants the party to commit to an in-out referendum on Europe.
Mills, chairman of Labour for a Referendum and co-chairman of Business for Britain, writes: "The EU crucially lacks democratic accountability and hence the electoral support and endorsement it so badly needs.
"To much too great an extent, there is no European demos, no shared culture, no confidence that groups will not seek to take advantage, no sense of the common good, no shared story of how we got to where we are today, no common view of obligations to future generations, no shared approach to law, and no common attitude to personal freedom, individual responsibility, civil society and the pursuit of public purposes in organised private life."