Small business owners have been urged to allow staff to watch England's World Cup match with Slovenia on Wednesday.
A survey of more than 140 firms by the London Chamber of Commerce found that two-thirds were not making any special arrangements for the 3.00pm kick off.
"Not everyone has caught World Cup fever, but there are people all around the UK who would like to support their countries at home, in the pub, or on the radio or internet at work," said TUC general secretary Brendan Barber.
"To avoid any tensions, bosses should discuss the issue with their staff. We would encourage them to let people watch the games if they like, and then claim back their time afterwards. That way, everyone wins."