A crippling national postal strike planned in the UK for tomorrow looks inevitable after last-ditch talks ended without agreement.

Customers were urged not to post any letters tomorrow to ease the UK’s postbag as workers prepare to stage a 24-hour walkout in a row over pay and jobs.

The first national postal strike in the UK in a decade was threatened today after union leaders decided to ballot 130,000 postmen and women over industrial action in a row over pay.

Royal Mail today vowed to “fight for every letter” following the New Year’s Day postal revolution in which it will lose its 350-year monopoly on deliveries.