Royal Mail has announced plans to make up to 6,000 people redundant by next August, blaming ongoing strike action and rising losses at the business.

The postal company said it will begin notifying workers of its plan, which aims to reduce its overall headcount by a total of 10,000.

The majority of the cuts will be made through redundancy while the rest will be achieved through natural attrition.

Royal Mail also said it expects its full-year losses to hit £350m.

It said this included “the direct impact of eight days of industrial action” as well as lower volumes of parcels being posted.

But the firm warned that losses could reach as much as £450m “if customers move volume away for longer periods” following strike action.

Royal Mail’s chief executive Simon Thompson said: “This is a very sad day. I regret that we are announcing these job losses. We will do all we can to avoid compulsory redundancies and support everyone affected.”

Royal Mail workers, who are members of the Communication Workers Union, this week began a fresh round of strikes over pay and conditions which will include 19 days of industrial action, including Black Friday.