The increasing prevalence of technology such as mobile phones and Blackberries means that employees rack up an extra 20 days of unpaid work each year, according to new research.

Figures produced by Office Angels suggest that seven per cent of employees surveyed felt under pressure and suffocated by their bosses and clients because they were constantly in communication with work.

Meanwhile, one in ten reported constantly checking their work outside of office hours.

Commenting on the findings, David Clubb, managing director of Office Angels, said: "It’s important that you maintain a work-life balance and keep work in perspective.

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"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."

Research published last month by Yahoo! revealed that 39 per cent of workers will reply to work emails or calls promptly even outside of working hours.