Voters overwhelmingly believe there should be a referendum on Britain's relationship with the European Union, according to an opinion poll.

The survey by Populus for The Times (£) found almost half - 49% - wanted a referendum immediately while a further third - 33% - believed there should be one "in the next few years".

Fewer than a fifth - 18% - saw no need for a referendum in the foreseeable future.

A third - 32% - wanted the UK to be part of a single market in a wider European community as against 40% who did not, while 27% said they did not know.

A referendum is favoured by many backbench Tory MPs, 81 of whom rebelled against the government to call for a public vote last year.

However a report from the Open Europe, arguably the country's most eurosceptic think-tank, has warned that a British exit from the EU would cause "unpredictable political and economic risks".

As the Guardian reports, Open Europe suggests that continued membership remains "the most beneficial arrangement" for Britain.

Chancellor George Osborne this weekend warned that the UK faces a lost decade unless the eurozone crisis is brought under control.

While the planned 100 billion euro in European Union rescue funds has eased some nerves over Spain, further storms lie ahead for the eurozone.

The next key date for the euro currency union is Sunday when Greece holds an election that is being seen as a referendum on whether to stay in the eurozone or reject painful austerity measures.

:: Populus interviewed an online sample of 2,006 adults between June 8 and 10.