STRESSED-OUT office workers are spending more than 20 hours a week worrying about problems at work, according to a survey released today.

Recruitment consultants Office Angels says that it is the equivalent of workers putting in an extra three days' work a week without pay.

Research among 1,500 employees found that two-thirds admitted to spending more than 20 hours a week thinking or talking about work.

Thirty per cent said work was always at the back of their mind and more than a quarter owned up to dreaming about their job.

A third of office workers admitted to "Sunday night syndrome", becoming depressed when thinking about the working week ahead.

Only 12 per cent said they could switch off as soon as they leave the office. Paul Jacobs, of Office Angels, said: " Unfortunately, physically leaving the office does not necessarily mean that you can switch off.

" However, apart from extenuating circumstances, time outside of work should be dedicated to yourself -- after all you have earned it.

" It is always best to try and resolve issues and concerns before you leave the office, or even better, try to pre-empt them." Office Angels have the following advice to avoid spending your own time on work:

Write a list of jobs to be done before you leave the office.

Do not let the sun set on issues or worries.

Develop interests outside work, take exercise or learn new skills

Detox your desk, throwing away unwanted paper.