European Union lawmakers called on Thursday for an end to a loophole that allows British firms to break working time limits laid down by the bloc's laws.
The European Parliament's Employment and Social Affairs Committee narrowly voted to urge the European Commission to suggest ways to narrow the scope of this opt-out, used most extensively by Britain, and eventually to scrap it altogether.
They want even more urgently to clarify the way working time is defined - a critical issue for the EU's health sector after a court ruling last year forced Germany and others to count all time that doctors spend in hospital as standard working time.
The Commission is asking for feedback on the so-called working time directive, which says employees cannot be forced to work more than an average of 48 hours per week, as a pre-cursor to suggesting possible changes.
While the Commission's consultation document did not specify any plans to change the opt-out, it focused on failures to apply the spirit of the EU law in Britain, where 16 percent of employees regularly work longer than 48 hours per week.
One way firms get around the rules is by asking prospective employees to sign the opt-out at the same time as their employment contract, a practice which effectively compromises a worker's freedom of choice, according to the Commission.
"We are asking the Commission to come up with changes as quickly as possible after the consultation period is closed," said the chairman of the Employment and Social Affairs Committee, Theo Bouwman.
"The main objective is to solve the problem of how to interpret the directive when it comes to health workers and workers in similar sectors, such as firemen. We also have to find a solution to the general opt-out used by the UK which is unacceptable."
The committee voted to call for an end to such practices. The issue will now be put to a vote by the full parliament within a month.
But not all members of the parliamentary committee were happy with this position.
"By signalling that they wish to see this clause go, Labour MEPs have broken ranks with their own government's supposed commitment to a flexible labour market and a competitive UK economy," said Liz Lynne, a British Liberal Democrat on the committee.
"Of course there must be adequate provision against workers opting out under duress, but this is not best achieved by removing the opt-out altogether."
The Commission said parliament's view was important as it would be a key player if the working time law needed to be changed but that it would reserve final judgement until its consultation period was over, at the end of March.