Bridget Galton and family follow an interactive trail around London Zoo in search of the real animals in Rod Campbell’s classic story book

I wrote to the Zoo to send me a pet. So begins Rod Campbell’s much loved lift-the flap storybook that is now 35 years old.

To mark the occasion, London Zoo has created a self-guided trail and interactive hub for young visitors which starts at a giant crate modelled on the ones in Campbell’s bestselling book.

Inside, kids can sit on squashy multi-coloured beanbags for storytelling sessions and discover lifesized versions of the animals who are despatched to the writer in crates - then sent back as unsuitable.

They can then roam around the Regent’s Park attraction, collecting stamps including a giraffe, grumpy camel, naughty monkey, fierce lion, jumpy frog and scary snake.

Familiar to parents the world over, the interactive classic has sold more than eight million copies worldwide and is published in 20 languages by Macmillan children’s books.

The 71-year-old author attended the launch this month to sign copies of his book and blow out the candles on a specially baked cake.

My five-year-old and eight-year-old were among the first to strike out around the zoo collecting the stamps on their card.

The joy of the trail is in discovering the real life animals in the book. The giraffe stamp takes you to the Zoo’s Africa section where we also found pygmy hippos taking a bath and zebras basking in the spring sunshine.

We found the frog and the snake stamps in the reptile house along with a crocodile and turtles and the chance to touch some real crocodile skin.

We then searched out the monkeys and the Asiatic lions in the zoo’s newest attraction which is themed around India’s Gir National Park.

Once completed we collected a sticker and explored the rest of the zoo, from the Penguin beach, to watching the two tiger cubs’ game of rough and tumble, and the infant gorillas teasing their mum.

Penny Hamilton, head of marketing and events at ZSL said:

“We’re sure children and adults will love delving beyond the pages of Dear Zoo. Rod Campbell’s tale of a child who writes to the Zoo to send them a pet has enchanted children for over three decades - now everyone can be part of the story here at London Zoo.”

Trail is included in the normal zoo entry price until April 17. Zsl.org