POSTAL workers in Oxfordshire returned to work this morning but union leaders are warning it could be Friday before any mail is delivered.

Communication Workers Union representative Bob Cullen said there was a backlog of "millions and millions" of letters and parcels at the Oxford Mail Centre in Cowley.

As a result, staff who would normally be delivering mail have been called in to help with the mass sorting operation.

Mr Cullen said: "The problem is that it is not just mail backed up in the system - the public and businesses have been told to hold back until today and there is going to be a deluge of new mail."

Meanwhile, postal workers in the Liverpool and Glasgow areas refused to go back to work today and there are fears the wildcat action could spread nationally.

The situation is also likely to remain chaotic next week with strike action staggered across the service on different days.

Talks over pay, jobs and pensions remain deadlocked, although the CWU claims there has been significant movement.

But Royal Mail chief executive Adam Crozier fuelled the flames by claiming Royal Mail staff were paid 25 per cent more than workers in rival post firms.

He added that other companies in the business were 40 per cent more efficient, which is why the Royal Mail wanted a long-term solution to the current dispute to help it compete more effectively.