Parents have been left furious after an advent calendar sold in John Lewis made it seem like Christmas was coming a full week early.

Many customers who opened up their December 2 window on their Christmas calendar today spotted the unfortunate mistake - as they were told Christmas was coming in 16 days' time, December 18.

Those who bought the calendar took to Twitter to point out the mathematical mistake.

Nick Macey wrote: "I think you have an error on your advent calendar. Opened number 2 this morning to be told Christmas is 16 days to go. "

John Lewis said in a statement: "We're so sorry for the disappointment caused when customers opened up this advent calendar.

"The supplier is working closely with us and other retailers to put this right as quickly as possible, and for any customer who has bought one of these advent calendars from John Lewis we will offer them a full refund."

Supplier Woodmansterne added: "We are devastated to learn there is a mistake on one of our advent calendars."