The European Parliament has voted to end to Britain's opt-out from the 48-hour working week, provoking the wrath of employers’ groups and the UK government.
While the vote is not legally binding, it has alarmed business leaders because it sends a signal that the European Commission should support the trade union campaign on the issue.
Twenty-three British Labour Euro MPs also ignored their own party and voted in support of the motion calling on all member states to scrap opt-outs and enforce the 48-hour limit on working time on all countries.
But in London, the government said that it would continue to fight to maintain the UK’s opt-out. "We believe that everybody should have the legal right to work longer than 48 hours if they choose to do so," said a Government spokesman.
"The key word is 'choose'. No one should be forced to work beyond 48 hours if they do not wish to. But equally they should not be forced to work less than 48 hours.
"There are many reasons why some people willingly work longer hours, taking advantage of overtime to earn more money, for instance. But of course if any employer is exploiting the system we want to know about it."
Susan Anderson, CBI Director of Human Resources Policy, said the move would be "a serious blow to the individual's right to govern their own time and to the flexibility employers value".
She said: "People don't want the EU interfering with the details of their everyday lives. They want the freedom to make their own decisions about the hours they work.
"Under current law, nobody can be forced to work more than 48 hours a week. The directive correctly allows people to say 'no' to long hours and now we must preserve the right to say 'yes'.
"Failure to save the opt out will stop thousands of people from working overtime, trigger a huge increase in bureaucracy and put UK firms at a competitive disadvantage compared to EU firms.
"This is a vital flexibility for the UK economy. Our competitors have other flexibilities: the Netherlands exclude far more workers while others strike deals with unions in order to maintain flexibility over hours."
Responding to claims that many UK employers are forcing staff to sign opt outs, she claimed that: “nobody has presented convincing evidence that large numbers of employees feel exploited or coerced. Indeed, claims of widespread abuse are wildly exaggerated.
"There may be isolated incidents of unacceptable behaviour and we accept the need to address this but it is not a matter for the EU - it must be done at the national level. The CBI is trying to deal with these concerns by joining discussions on the issues with the TUC and the government."
But Trade Union Congress general secretary Brendan Barber welcomed the vote. "This is a very welcome decision from the European Parliament," he said. "It increases the pressure on Europe to end the UK opt-out, the only sure way to start to tackle our long hours culture, and leaves the UK looking isolated.
"The opt-out means that the directive has had little, if any, impact on working hours in the UK. We still work the longest hours in Europe."