Twenty million working days could be lost due to stress as 50% of employees report higher stress levels than last year.

In 2007-2008 13.5 million working days were lost due to stress, according to the Health and Safety Executive and, with a 50% increase, these figures could top 20 million.

The findings come in a report from Croner and YouGov, which also found the most common reason for stress is work (63%), followed by finances (62%) and the economy (49%). Health concerns was the fifth most common cause of stress cited by 22% of respondents and the impact of work colleagues (21%).

Gillian Dowling, employment technical consultant at Croner, said: "This should be a real wake-up call for British bosses who may be in denial that stress is a concern in their organisation.

"If stress levels are running high it will be in the employer's best interests to deal with this from a legal and business point of view. Stress issues should not be put on the back burner as it has a direct effect on reputation and customer satisfaction."