Royal Mail has announced it will begin a process to make 5,000 to 6,000 roles redundant by August next year.

The announcement, made in a trading update by the postal service’s parent company, has been blamed on industrial action taken by Royal Mail workers, delays in improving productivity and falling parcel volumes.

Parent company, International Distributions Services plc, said it had a loss of £219m for the first half of this financial year.

Around £70 million of that loss was attributed to “direct negative impacts” from three days of industrial action.

Members of the Communication Workers Union (CWU), who represents Royal Mail workers, had been engaged in strike action over pay and conditions.

Around 115,000 Royal Mail staff walked out over pay and conditions in what the CWU said is the biggest national strike of any sector this year.

Twenty-one days are to be affected by the strikes.

Commenting on the announcement CWU general secretary Dave Ward said: “The announcement is the result of gross mismanagement and a failed business agenda of ending daily deliveries, a wholesale levelling-down of the terms, pay and conditions of postal workers, and turning Royal Mail into a gig economy style parcel courier.

“What the company should be doing is abandoning its asset-stripping strategy and building the future based on utilising the competitive edge it already has in its deliveries to 32 million addresses across the country.

“The CWU is calling for an urgent meeting with the board and will put forward an alternative business plan at that meeting.

“This announcement is holding postal workers to ransom for taking legal industrial action against a business approach that is not in the interests of workers, customers or the future of Royal Mail. This is no way to build a company.”