Almost 130 staff walked out of the office in Bridgwater, saying they were owed time and money.

The workers also say they have been harassed by management at the Somerset-based Royal Mail depot.

But managers insist it is their duty is to discipline workers who are not succeeding in their tasks.

We need to get back to talking, not having people standing around

John Ainley, Royal Mail

Clive Wellsford of the Communication Workers' Union said: "Staff have walked out as a result of the treatment received.

"The workers feel an agreement we struck with management has been ignored.

"Management must talk to us, but they refuse to do so until we go back to work.

"We hope enough pressure can be placed on them to get back to meaningful discussion."

'Standing around'

John Ainley, Royal Mail's operations manager in the Taunton area said: "We need to get back to talking, not having people standing around, depriving customers of our service.

"If there were allegations of bullying, we would take them seriously.

"If we have to challenge people on their performance.

"That is all part of what management is supposed to do."