Police are on the hunt for a stalker who calls himself "Gordon", whose distinctive poison pen letters are written on animal-themed greeting cards.

The stalker has waged a six-year stalking campaign against a woman, but police believe his unusual style and consistent stationery choices could hold clues to his identity.

Police said the cards have been sent over six years but they have become more graphic and threatening in nature over the past two years and include threats to commit rape.

The offences have all happened in Bristol and we believe the offender is sending the cards from somewhere within the Bristol postmark area.

Shopkeepers who sell the cards have been asked to be vigilant and to see whether they recognise his handwriting.