The European Parliament's employment committee yesterday voted to end the UK opt-out from the European Union's working time directive.

Labour MEPs defied the Westminster Government by backing moves to end the UK's opt-out from the directive, which aims to limit the working week to 48 hours. But ministers in Whitehall have insisted that they will maintain the opt-out.

The directive states workers should work no more than 48 hours a week, unless they want to, and that temporary workers should have the same rights as permanent employees. The key element of a deal struck in 1993 let Britain keep its long hours culture by allowing it to retain an opt-out to the 48-hour limit. Other countries also have opt-outs for specific sectors.

In return, Westminster agreed to EU legislation giving temporary workers the same rights as permanent staff, unless trade unions and employers agree otherwise.

But yesterday the employment and social affairs committee of the European Parliament voted to scrap the opt-out, a decision which goes directly against the position of the Prime Minister.

Labour MEPs were among the 35 who voted in favour of scrapping all opt-outs within three years, repeating the parliament's position from 2005, when members argued the 48-hour week protected against exploitation and accidents. Thirteen were against.

Negotiations will now begin between the Parliament and EU employment ministers, ahead of a vote by the full parliament in December.

Business Secretary Lord Mandelson said the committee's decision was "not surprising", but added: "We will continue to stand firm to protect the opt-out."

Unions welcomed the move, but businesses said it would damage their flexibility.

TUC general secretary Brendan Barber said workers would be "heartened", adding: "Our long hours culture, which has been shored up by the opt-out, has left many workers' health at risk."

Alistair Tebbit, head of EU and employment policy at the Institute of Directors, said: "MEPs have made a big mistake by voting in favour for abolition of the opt-out from a maximum 48-hour week. As the EU enters recession, employers need more flexibility, not less.

"If the opt-out goes it would become much harder for businesses to adjust the working hours of employees to meet changes in trading conditions. These new restrictions would impact on business performance and ultimately destroy jobs."