Hopes of a breakthrough in the postal workers’ dispute faded tonight as union leaders and managers struggled to resolve a row which has crippled mail deliveries across Britain.
Another marathon day of talks failed to produce a solution to a conflict which has now spread across the UK.
A huge backlog of millions of items of mail continued to mount, forcing the Royal Mail to seal post-boxes in London.
More than 20,000 postmen and women remained on unofficial strike across the capital and in parts of Essex, the North West, Hampshire, the Midlands and Home Counties.
Communication Workers Union leaders and Royal Mail managers met for almost 12 hours yesterday and again for several hours today but optimism that a settlement could be reached was dashed.
The company’s chief executive Adam Crozier unexpectedly joined the talks last night, dealing directly with the union’s deputy general secretary Dave Ward.
Both men said progress had been made yesterday and there were behind the scenes moves aimed at paving the way for a deal to be announced today.
But in the event, there was little progress made today and the two sides are set to continue negotiations tomorrow under the chairmanship of the reconciliation service Acas.
Some union officials said media interviews given by Mr Crozier today, in which he warned of possible legal action to try to end the wildcat strikes, had hit the chances of a deal.
Mr Crozier made it clear that the Royal Mail was facing increased competition and could not afford to face continued industrial action.
He also said that an increase to the London Weighting allowance, which is at the heart of the row, could not be improved.
The conflict started two weeks ago when a number of drivers in Southall, west London, returning to work after an official London Weighting strike were suspended.
The union claimed the Royal Mail was trying to intimidate and bully workers into agreeing unacceptable working practices.
This was denied by the Royal Mail, which has said it was merely implementing a back to work agreement, which had been approved by the union.
Wildcat strikes have spread over the past two weeks, partly as a result of the Royal Mail trying to move bags of letters from strike-hit areas to other centres.
The Royal Mail has sealed most of the 13,500 post-boxes in London because of the crisis and now fears that competitor companies could try to take some of its business.
Industry leaders have pleaded with both sides to try to end the dispute because of the damage it is having on companies across the UK.
A growing number of small firms in particular are losing work because cheques, invoices, orders and other vital documents are being held up.