The UK is one step closer to losing its individual opt-out clause in the Working Time Directive, but it could still be another five years before employers need to amend working practices.
Last week, the employment committee of the European Parliament voted to remove the clause, which allows employees to voluntarily work more than 48 hours a week, by 2010.
The committee's vote signals the final stages of a process which has dragged on for years.
The decision - made despite massive opposition from business groups - now goes to a final parliamentary vote next month, which then has to be ratified by the EU's Council of Ministers, before the opt-out can be ditched. If this happens it is estimated that employers will be given until 2010 to comply.
Employers groups also want the government to stand firm against European proposals to shorten the current extended period of 52 weeks used to calculate average weekly hours where there is a workplace agreement.
They say they would be better equipped to deal with fluctuating demand if they could average staff working hours over a year, rather than the statutory 17-week period favoured by the European legislators.
David Yeandle, deputy director of employment policy for the manufacturers' organisation EEF, said the task was now about damage limitation.
"It is an exercise to minimise damage and maximise opposition to [the removal of the opt-out]," he said. "The important message to the government is this is not a signal to start compromising. It must stand firm and eyeball-to-eyeball with Brussels," he said.
Loss of the opt-out would harm numerous sectors in the UK such as construction, transport, hospitality and leisure by reducing labour market flexibility, according to Michael Ball, employment partner at law firm Halliwells.
The British Hospitality Association (BHA) estimates the cost to industry would be at least 200m due to extra training and recruitment outlay.
The Chartered Institute of Personnel and Development, which supports retaining the opt-out, said there could be pressure on wages to increase if hours were to be cut, as well as difficulties with recruitment.