The Vote Leave campaign group has published a list of 250 business leaders whom it says support Britain leaving the EU, including Luke Johnson, chairman of Patisserie Holdings.
Johnson was among the signatories backing the Brexit campaign, according to a BBC report that aired on 26 March. The list also includes former HSBC chief executive Michael Geoghegan and the hotelier Sir Rocco Forte.
But Britain Stronger in Europe said Vote Leave could not find a business to officially back it, as those listed supported it in a “personal capacity”.
A referendum on whether the UK should stay in the EU will be held on 23 June.
Last month, heads of 36 of the largest listed companies in Britain signed a letter urging voters to remain in the EU.
Vote Leave also announced that its business council would be chaired by John Longworth, who resigned his role as director general of the British Chambers of Commerce (BCC) earlier this month.
The council, made up of business leaders, will talk to businesses around the country to make their argument for an EU exit.
It will make the case that EU membership is holding back British business and will initially be made up of members from the board of campaign group Business for Britain.