As Christmas nears, British TV screens are filled with heart-warming tales of lonely penguins, family reunions and homesick soldiers in an attempt to get customers to part with their cash.

More and more retailers are ditching traditional product ads for mini movies about love and friendship that have become a national talking point, ranked against each other by the media and subject to parody online.

High-street department store John Lewis, which started the trend a few years ago, again leads the pack with a tear-jerking tale of a little boy who makes his lonely toy penguin's Christmas by buying him a mate.