The Confederation of British Industry - representing 190,000 businesses employing nearly seven million people – has released a report making a strong case for the UK remaining in a reformed EU.
The CBI released its study as UK Prime Minister David Cameron prepares to outline Britain's renegotiation demands. It stated, "the disadvantages [of leaving the EU] are significantly outweighed by the benefits [of staying in]" with "the Prime Minister's push for reform giving a window of opportunity to maximise those benefits."
The report has been welcomed by pro-EU MEPs and leading industry figures, who say it offers further proof that the UK will benefit from continued membership.
Glenis Willmott, Labour's Leader in the European Parliament, said: "Today's CBI report is the latest evidence that we are better off inside the EU - better for businesses, better for workers, better for consumers.
"It also puts to bed the claims of some sceptics that business would 'thrive' if 'freed' from the 'constraints' of the EU - the CBI has said very clearly that nothing less than full membership of the European Union is in Britain's interests, pointing out Norway and Switzerland follow EU rules but have no say over them.
This opinion has been shared by leading figures from business, who cite ease of access to the EU single market - something the UK would have to spend years renegotiating if it left the EU - as one of the key reasons for remaining part of the political bloc.
Andy Wood, Chief Executive of Adnams brewery, said, "We are making British beer popular across Europe, selling easily through the EU single market to our largest export market, Sweden. This means we can continue to grow our 420 strong workforce back home."
George Gillespie, Chief Executive of HORIBA MIRA - a car industry supply business - said, "As one of the largest export markets for cars manufactured in the UK, the EU single market is vital to thousands of businesses in the automotive industry supply chain."
Aside from access to the single market, the report also highlights a number of other reasons for remaining in the EU. These include the importance of having a single of trade rules rather than 28; opening up access to a third of the world's trade and the role that EU membership plays in attracting foreign.
While acknowledging that, "it is hard to quantify many of the benefits of EU membership," the CBI research estimates that membership is worth about four to five per cent of national income - equivalent to about €4000 per household. This is a similar figure to the one released by the Centre for Economics and Business Research - an economic forecasting company - in a report commissioned by the ‘Britain Stronger in Europe’ group.
However, Sajjid Javid, UK Conservative business secretary, has accused the CBI of bias. He has been criticised the CBI for thinking, "the UK should remain in the European Union no matter what."
Dominic Cummings, campaign director of the anti-EU ‘Vote Leave’ group, said: “The CBI leadership does not represent business opinion. It’s campaigning to stay in the EU regardless of the terms. It has zero credibility on the EU and the public won’t trust it.”
A referendum on British membership of the EU is expected in 2016.