Parents have been urged to stop pretending Father Christmas is real in case the "lie" damages relations with their children.

Spinning stories about Santa risks undermining a child's trust and is morally suspect, according to two experts.

Psychologist Professor Christopher Boyle and social scientist Dr Kathy McKay also condemn the idea of a "terrifying" North Pole intelligence agency which judges children to be nice or naughty.

Writing in the respected journal The Lancet Psychiatry, they argue: "If they (parents) are capable of lying about something so special and magical, can they be relied upon to continue as the guardians of wisdom and truth?"

In addition they suggest parents may not be motivated by thoughts of their children but a selfish desire to re-live their own childhood.