Check and double check your facts before committing your story to paper, I was always told as a trainee journalist.

It's a lesson that obviously hasn't been learnt by scribes on the Daily Mirror. The paper today led with a story that is set to become one of the all-time journalism cock ups (literally.)

"It's a Boy" declares today's front page, "Exclusive - Macca baby a month early!"

"I think they are going to call the baby Joseph after Paul's uncle," a source close to the McCartney family was quoted as saying.

A great scoop for the Mirror....except...er....it's not a boy. It's a girl.

Biology lesson for all Mirror hacks...Boy babies have willies. Girl babies do not.

Unless the McCartneys' new arrival is a hermaphrodite.