"Unofficial and unlawful" strike action was taken by postal workers at Dalkeith Delivery Office last week, according to Royal Mail.
Both postmen and office staff took unofficial strike action mid morning on Monday, June 22. They returned to work the next day and took unofficial action again last Wednesday. The strikers returned to normal working duties on Friday morning.
A spokesman for Royal Mail said: "The industrial action in Dalkeith was unofficial and unlawful.
"The Communication Workers Union repudiated the action and advised its members to return to work."
But Willie Marshall, of the CWU, told The Advertiser staff believed they were being "bullied, intimidated and harassed" by managers, leading to the wildcat strike action.
He added: "There's a ballot taking place this week and we presume we will get a massive 'yes' vote."
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