I've searched and searched the internet but can't find any sign of this book anywhere. Help!

As a child I remember reading a book about a young girl who visits a magic show and ends up being whisked into a magical land (along with a horse) after being asked to take part in the act. She and the horse (which can now talk) meet a few new friends (one reminded me of Stan Laurel) and then journey through a series of strange lands - I can recall a land which made everyone very depressed and another that was filled with bureaucratic egg-like people - all in order to save the world from an invasion of giant spiders. I think they were also searching for the magician's golden key, which they needed in order to return home.

I also recall that it was a rather large, board-backed book and it might have been called something like The Magician's Key.

Sound familiar to anyone? I would ask my mum but that would mean speaking to her and I doubt that she would remember it anyway.

I really hope somebody here had this book. I'd love to get hold of it again.

No, but it sounds great!

I would ask my mum but that would mean speaking to her

Lol. I feel your pain.