The Institute of Directors (IoD) has urged the European Union not to abolish the UK’s opt-out from the 48-hour working week, claiming that British firms would “lose their competitive edge” if staff could not complete overtime.

But the Trades Union Congress (TUC) attacked business groups for wanting to keep the opt-out and called on the EU to enforce the 48-hour week in the UK to protect workers’ health.

The clash between the business and trade union giants came as the EU ended its consultation period on the Working Time Directive (WTD) yesterday.

The WTD requires employers to limit their employees to a 48-hour week. Although all EU members have signed up to the directive, the UK has secured an opt-out which gives staff the option of waiving their rights in order to work overtime.

The IoD said that it firmly supported the opt-out, claiming that 76 per cent of its members would find it impossible to run their businesses as efficiently if the 48-hour week was enforced. A massive 90 per cent of IoD members supported the opt-out.

James Walsh, of the IoD, said that Britain’s flexible approach to working time gives our businesses a vital competitive edge.

“The opt-out cuts both ways – employees who choose not to exercise it retain their right to work no more than an average 48-hour week, but many value the freedom to work more than 48 hours – and to be paid more for doing so.

“Competitiveness would be badly undermined if the British opt-out were scrapped or restricted,” he said.

However, the TUC repeated its demands that the UK’s opt-out be scrapped, claiming that long hours harm employees’ health and damage productivity.

Trade union leaders said that employers were abusing the directive and pointed out that even if the opt-out was ended, staff would still be able to working an average of six eight-hour days a week.

Brendan Barber, general secretary of the TUC, said that strongest reason for ending the opt-out is the weakness of the arguments against it from employer lobbyists.

“The Chambers of Commerce tell us that long hours working has no effect on health, yet the risk of heart disease, chronic headache, irritable bowel syndrome, diabetes, stress and accidents at work are greater for long hours workers,” he said.