LONDON - Britain's top bosses should defend membership of the European Union by telling voters it is the best guarantee of prosperity, the head of the country's largest business lobby group will say on Wednesday.
Prime Minister David Cameron has pledged to renegotiate Britain's ties with Europe and then give voters an in-out referendum on European Union membership by the end of 2017.
Mike Rake, chairman of BT and deputy chairman of Barclays, will tell 1,000 chief executives and politicians to turn up the volume on the benefits of the European Union so that Britain shuns isolation.
"Business must be crystal clear that membership is in our national interest. The EU is key to our national prosperity," Rake, president of the Confederation of British Industry (CBI), will say at its annual dinner in London.
"Business has increasingly spoken out on this crucial issue and the time has come to turn up the volume," he will say. "The question is not whether the UK would survive outside the EU, but whether it would thrive."
The threat of a British exit, or 'Brexit', has already prompted some businesses to warn of the consequences for the world's fifth-largest economy and London, the only financial capital to rival New York.
Deutsche Bank said on Tuesday it was reviewing cutting its British presence in the event of a Brexit.
Rake will tell Britain's leaders to build EU alliances to make the union more competitive but will caution that EU treaty change - a current demand from London - is not essential.
"We support the Prime Minister's drive for a more competitive EU," he will say, according to extracts released by his office. "The EU can be more competitive without the need for treaty change."
Ahead of last year's referendum of Scottish independence, some senior business leaders said that breaking up the United Kingdom would hurt Scotland.
Leaders of oil giants Shell and BP and financial services heavyweights Royal Bank of Scotland, Standard Life, and Barclays, all warned against Scotland leaving the UK.
Companies operating in the car industry have already come out in favour of the EU, though there is no centrally organised pro-European campaign yet.
The chairman of construction equipment company JCB said on Monday that Britain need not fear an exit from the EU.