Strike means this is the last day for first-class Royal Mail deliveries

Royal Mail has warned customers that today is their last chance to send packages and cards first-class in time for Christmas as staff return to work after two days of strikes.

The company said it had been forced to bring forward its deadline by five days because of the industrial action.

It is already too late to send items second-class. Special and guaranteed-delivery items can be sent for Christmas until Wednesday.

• Royal Mail strike dates in December and last Christmas posting days

The company blamed the Communications Workers Union, claiming it was “holding Christmas to ransom”. The CWU accused Royal Mail of ignoring a “peace offering”, saying its “sole intention” was to “destroy the livelihoods of over 115,000 postal workers”. Further strikes could follow