LONDON, Oct 23 (Reuters) - Britain's postal union staged a second consecutive day of strikes on Friday, with about 78,000 delivery and collection staff absent from work, crippling mail deliveries and dealing a blow to Prime Minister Gordon brown.
The Communication Workers Union (CWU) called strikes over pay and job cuts, and to protest modernisation plans for the postal service.
About 42,000 mail centre staff and drivers walked out early on Thursday morning, and later that day the CWU said it planned a fresh wave of strikes, to begin on October 29.
Royal Mail [GBPO.UL], whose business has declined by some 10 percent annually in recent years, says modernisation is essential if the state-owned company is to fight off competition from more specialised delivery services and the Internet.
Mail has already been held up by previous regional postal disputes, and an estimated 150 million parcels and letters could get caught up in the latest backlog.
Brown has said the strikes were self-defeating and would lead to more job losses. He promised that the government would do everything it could to resolve the dispute.
The strike is likely to embarrass Brown's Labour Party, which receives a large chunk of its funding from the trade union movement.
The opposition Conservative Party, which is well ahead in opinion polls before a national election due to be called by next June, has attached Brown's handling of the dispute.
Conservative leader David Cameron said the government's failure to go ahead with a planned part-privatisation of Royal Mail had galvanised union militancy.
Labour says it shelved its plan to sell up to 30 percent of the company earlier this year because it could not find a buyer during the global economic crisis. But Brown also faced strong opposition from postal workers and within his own Labour Party.
(Reporting by Catherine Bosley and Avril Ormsby; Editing by Jon Boyle)