Major British business figures warned Prime Minister David Cameron on Wednesday that the renegotiation of the country's relationship with Europe could risk its exit from the EU, with "damaging" consequences for the economy and businesses.
Ten top business leaders -- including Virgin tycoon Richard Branson, WPP advertising agency chief executive Martin Sorrell and Rio Tinto chairman Jan du Plessis -- also called for "urgent" EU reform in an open letter to the Financial Times.
"We urgently need more EU reform, not least of the working time directive and the antiquated EU budget, and completion of the single market in services such as digital, telecoms and energy," the letter read.
"Britain should be forthright in seeking the lead to achieve these changes. But equally, we must be very careful not to call for a wholesale renegotiation of our EU membership, which would certainly be rejected."
Cameron is due to give a major speech this month about Britain's strained relationship with the EU, but has already said he wants to renegotiate the conditions of its membership with the 27-country bloc.
"To call for such a move in these circumstances would be to put our membership of the EU at risk and create damaging uncertainty for British business, which are the last things the prime minister would want to do," the letter added.
"We need a strong reformed EU with Britain at the heart of it."
The premier had vowed on Sunday that he wanted to serve as prime minister until at least 2020 to oversee a range of reforms -- including a renegotiation of Britain's relationship with Europe.
The letter was also signed by Roger Carr, president of powerful business lobby the Confederation of British Industry (CBI), as well as London Stock Exchange chairman Chris Gibson-Smith and BT chairman Michael Rake.