Europe Economics report, commissioned by Business for Britain, says 'only very considerable reforms' will prevent this
Former EU trade commissioner and Labour lord plays down Ukip electoral success.
Chancellor George Osborne attacks both left and right in speech to Confederation of British Industry.
The prime minister has now ruled out resigning over two referendums.
The prime minister's pledges over an in-out vote are aimed at winning over Ukip voters.
UK Prime Minister David Cameron has said that the UK Independence Party won't be able to change a thing in Europe, even if they succeed in May's European Elections.
Shadow chancellor Balls says in speech to BCC he backs markets, but would intervene where necessary.
Lib Dem and Ukip leader go head to head over UK membership of EU while Cameron looks elsewhere
Ed Miliband receives mixed reviews for EU policy leaving Tories in a fix.
Britain's opposition expected to offer same in-out choice to voters on EU membership.
Business for Britain is calling for a radical overhaul of the European Union.
Business reaction to Labour's tax hike predictable but bigger spectre stalks debate.
Britain's business secretary says uncertainty over a 'Brexit' is spooking investors.
US investment bank joins a line of institutions that support the UK's EU membership
Banking giant also warns UK leaving EU will reduce investment from international companies
CER says UK would struggle to maintain trade with other EU member states if it left.
Osborne makes a speech makes the case for European Union reform.
Osborne will tell EU in a speech that structural changes are needed to survive
Nigel Farage 'should join televised election debate' with Cameron, Miliband and Clegg.
Business Secretary plays down fears UK will quit European Union, even as prospect of 2017 referendum looms.
Cameron tells CBI conference that public support over European Union membership is waning
Labour's shadow chancellor Ed Balls to tell CBI conference he shares vision of reformed Europe - but from the inside.