Business lobby group the British Chambers of Commerce has refused to comment on reports that its director general, John Longworth, had been suspended from his post after after suggesting Britain would be better off outside the European Union.

At the BCC’s conference on Thursday, Longworth told reporters that Britain would be left, “sitting on the margins” of an “unreformed EU” if voters chose to remain in the EU at the 23 June referendum. After a Brexit, he said, Britain could have a “brighter economic future for itself”.

But with a recent survey showing that two thirds of the BCC’s members reject Brexit, Longworth came under pressure after his remarks. He later stressed that he had spoken in a personal capacity, but it was suggested on Friday that he had been suspended. A spokesman said: “We’re not making a comment at this time”.

Both sides of the referendum debate have been keen to sign up major business leaders to their cause and Longworth’s stance was greeted as a coup by Eurosceptics. But the BCC’s official position is to avoid campaigning for either side of the argument.

Will Straw, executive director of Britain Stronger In Europe, who described Longworth’s reported suspension as unusual, said: “This development shows how businesses do not wish to be misrepresented about their views in this debate. Businesses of all sizes, including a two-to-one majority of BCC members, have been clear that they value Britain’s place in the world’s largest free trade single market and worry about the uncertainty a vote to leave Europe could cause.

“This affair demonstrates that, while some individual businesspeople are campaigning to leave the EU, their views do not come close to representing the clear majority of British businesses – large and small.”

The turmoil within the BCC, which represents thousands of firms employing 5 million workers, underlines the difficult balancing act facing business groups as they seek to represent their members’ views in the run-up to the referendum. Anti-EU protestors at a CBI conference in November heckled the prime minister and held up a banner saying “CBI=Voice of Brussels”, after the business lobby group appeared to take a pro-EU stance.

A statement released earlier on Friday by the BCC said it would not “be campaigning for either side ahead of the EU referendum. The BCC will survey chamber member companies across the UK, report their diverse views, and inform the debate”.