The European Commission is taking the UK government to court for allegedly failing to enforce a directive that entitles employees to tea breaks.
'T' could spell trouble for the government
It further accuses the government of neglecting its working time rules, which unions say has cost staff millions of hours of leisure time.
The Commission is taking its case to the European Court of Justice.
A commissioner said the issues were "rest periods" and "undeclared working time" in the EU Working Time Directive.
Amicus - the UK's largest manufacturing, technical & skilled persons' union - complained to the EC about four years ago alleging the British Government was failing to introduce Working Time Directive rules.
It charged that existing UK regulations encouraged employees not to take breaks at work, which are required by law.
The law states employees should have breaks during the day as well as between each week or fortnight and longer breaks over the course of the year.
Opportunity to exploit
Roger Lyons, president of the Trades Union Congress and joint general secretary of Amicus, said: "As a result it is possible for workers to work 24/7 without a break and not breach regulations.
"Because of the climate of fear and downsizing in many workplaces, workers fail to take their legal entitlements to a tea break."
Amicus says the government has failed to protect as many as three million white-collar workers from companies pressuring employees to do extra work at home.
Its second complaint centres on staff working voluntary hours, discounting the average of 48 specified in the directive.
"While we welcome the legal action we would have rather the UK Government had chosen to apply the Working Time Directive by agreement," an Amicus spokesman said.
"However, we have waited too long and there is now clearly no alternative."