LONDON, Oct 21 (Reuters) - Negotiations failed on Wednesday to prevent a strike by Britain's postal workers this week and their union leaders said there will be further walkouts.
Thousands of staff working for the state-owned Royal Mail [GBPO.UL] are due to walk out on Thursday and Friday in a row over pay, jobs and modernisation.
The action is expected to severely disrupt mail deliveries.
Negotiations between the company and the Communication Workers Union made progress but were undermined by senior Royal Mail bosses and Business Secretary Peter Mandelson, the union said.
"Unfortunately the situation is the strikes will go ahead," said Dave Ward, the CWU's deputy general secretary.
Some 42,000 mail centre staff and drivers are due to strike on Thursday followed on Friday by 78,000 delivery and collection staff.
The Royal Mail and the government have warned the strikes will damage the company, put small firms that use its services in jeopardy and push clients to competitors.
Royal Mail's business has suffered in recent years as consumers and industry switch to the internet or more specialised postal services.
Mandelson said this week that Royal Mail had to modernise to survive and its finances would be pushed into the red by the strikes.
The government wants to sell up to 30 percent of the company to make it more competitive but set aside those plans earlier this year due to adverse market conditions and opposition from workers and Labour politicians.
Royal Mail has said it would hire 30,000 temporary staff to help cope with the backlog expected to be created by the strikes and a higher Christmas workload -- double the normal seasonal intake. (Reporting by Michael Holden; Editing by David Cowell)