LONDON – British postal workers are to be balloted in September for a national strike and thousands of Royal Mail staff are to take part in industrial action against job cuts over the next three days, a union said on Thursday.

Royal Mail condemned the plans for a national strike saying it beggars belief that the Communication Workers Union (CWU) would consider action as the company battles falling business.

The CWU said workers in areas such as London, Birmingham, East Anglia and Edinburgh would stage 24-hour strikes between Friday and Sunday as part of ongoing protests at cuts and the management's modernization plans.

It said for the first time since 2007 the action would involve Royal Mail drivers, meaning cross-county services would be severely disrupted.

The union also said it would hold a national strike ballot in September.

Postal workers are sick and tired of an incompetent management running their business into the ground, said Dave Ward, CWU deputy general secretary.

Workers are busier than ever and being treated badly. The current round of cuts in jobs and services is unacceptable.

He accused the company of reneging on a 2007 deal and imposing panic-driven cuts to jobs and services.

Royal Mail, which employs about 180,000 staff nationwide, said the CWU had failed to engage in talks over its pay and modernization plans.

The company has a large pension deficit and has seen mail volumes decrease by 10 percent annually because of competition from other operators and the growth of email.

The CWU is again saying one thing and doing another --publicly they say they want modernization yet they write regularly to members saying union policy is to oppose change on the ground, said Paul Tolhurst, Royal Mail's operations director.

They agreed with us only last week a timetable for further talks on change yet they now announce a national strike ballot. Their behavior beggars belief.

Last month the government suspended plans to sell part of Royal Mail due to adverse market conditions.

The proposal had been to sell up to 30 percent of the company to make it more efficient and competitive, but the part-privatization plan had been condemned by some Labour lawmakers and unions.

(Reporting by Michael Holden; editing by Mariam Karouny)