LONDON - Britain's Royal Mail won an injunction at London's High Court on Friday outlawing a new wave of postal strikes scheduled for next week.

The action comes as talks between union leaders and the Royal Mail continued to try to find a deal to end the industrial action that has brought huge disruption to the postal system.

After a hearing lasting one-and-a-half hours, Judge Timothy King granted the injunction to prevent members of the Communication Workers Union walking out again on Monday.

Talks to end the dispute over pay, pensions and shift changes had ended without agreement on Thursday after a day of unofficial strikes by hundreds of postal workers in parts of London and Liverpool.

The wildcat action involved workers at 30 of the Royal Mail's 1,400 depots.

One-day strikes planned for next Monday and Tuesday would have compounded the delays and disruption caused by recent 48-hour stoppages.

Although deliveries resumed on Wednesday, postal workers were left with a backlog of more than 60 million undelivered letters.

Royal Mail has warned customers to expect more severe disruption if the planned action goes ahead.

Prime Minister Gordon Brown has called on the CWU to end the strike, saying there was no justification for it.

Conservative Shadow Business and Enterprise Secretary Alan Duncan said the government should do more to end the dispute.

"Put simply, there is no urgency in trying to bring the postal strike to an end," he said.

Royal Mail is fighting private competition from rivals after losing its 350-year monopoly on postal services last year.

Its Chief Executive Adam Crozier says the company desperately needs to modernise to compete and that staff should be more flexible.

Union chiefs say that some working practices at Royal Mail amount to slavery.