One in five workers puts in an extra day's unpaid overtime a week, according to a TUC survey.

Londoners were found to be the most likely to put in added hours, averaging an additional eight hours and 12 minutes a week, followed by the Welsh at 7 hours 48 minutes a week and those in Northern Ireland at 7 hours 36 minutes.

Brendan Barber, TUC general Secretary, said that the figures were nothing to celebrate and suggested inefficiency.

"Millions are still putting in up to an extra day a week for free, but there are now some welcome signs that some employers are beginning to realise that endless hours of unpaid overtime are often a sign of an inefficient workplace, and not something to celebrate," he said.

"Most people enjoy their jobs, and don't mind putting in extra effort when there's a rush or an emergency, but that easily turns into the long hours culture of extra hours every week." Barber added.

The TUC study indicates a slight improvement in the UK's long hours culture. The percentage of people working an extra hour a week unpaid is now at its lowest level since 1992.

The TUC is dedicating Friday 24 February as their third Work Your Proper Hours Day and is urging workers who regularly do unpaid overtime to take a proper lunch break, and arrive and leave work on time.