A survey of 1,000 staff by recruitment firm Office Angels showed that seven per cent felt under pressure and "suffocated'' because they were constantly tuned in to work, while a similar number were angry that they could not switch off and escape work.

Companies are reaping huge returns by providing new technology to their staff because of the extra hours being worked, said the report.

But despite the "shocking'' statistics, two out of five of those questioned said they were grateful for technology, often believing it reduced stress levels by allowing flexible working and preventing e-mail build-up.

David Clubb, managing director of Office Angels, said: "It's important that you maintain a work-life balance and keep work in perspective. Occasionally we all need to work outside of normal hours, but this should really be the exception not the rule. Be disciplined about whether you really need to log on.''

Office Angels urged workers not to let technology dictate the hours they put in.