Daily Herald Archive photograph entitled 'Letters Pour in for Photos of Canine Star'. The black and white image shows Petra, the Blue Peter dog, sat at a table behind a mound of letters. A Keystone photograph dated 29 February 1964. Marked JP/766595.

Since Blue Peter began in 1958, there have been 24 pets on the show. The first of these was Petra, who appeared in 1962 and could often be seen alongside presenter Peter Purves, who she lived with. Pets were introduced to Blue Peter to teach viewers how to look after animals, and act as surrogate pets for those that did not have their own.

Because of this, viewers became very invested in the Blue Peter pets. In 1964, it was announced on one episode of Blue Peter that viewers could write in to receive their own picture of Petra. 60,000 letters were received, leading to this photoshoot where, according to the image caption, “she has had to try to answer all requests herself.”

Petra was one of Blue Peter’s longest standing pets, retiring in 1977.

Original caption reads:

Letters Pour in for Photos of Canine Star

Petra, the mongrel dog in this picture has a real problem: some 60,000 letters asking for photographs of her. Petra, who appears in Blue Peter, a BBC TV program for children, got the letters after an announcer said that viewers could write in for a picture of the dog. And then the deluge of fan mail started! And what's more Petra has no secretary - so she has had to try to answer all requests herself.

The description uses male pronouns although Petra was female.