The last recommended posting day for second class mail is Wednesday, December 18.
The last posting day for first class mail is Friday, December 20.
Anyone who misses these dates can still use the Royal Mail’s special delivery service up until Monday, December 23.
But mail bosses warned customers to post early this December to guarantee delivery and to make sure the full address is written clearly on the item of mail, the correct amount of postage has been applied and to always include the full postcode.
They said they were expecting a bumper Christmas mailbag. A spokesman said “We are encouraging customers to post early this December, a campaign that we have run since the 1800s to encourage people to beat the Christmas rush and make sure their letters and parcels arrive on time.”