Can you help me find this children's book?

[ButterflyBird]

Hi all, there's a children's book I've been trying to find for years but I don't know the title or author (not much to go on I know) but I'm hoping someone on here might remember it!

We were read a book when I was in Year 2 (1996/1997) and basically the premise was that a girl woke up one day and every time she told a lie it came true. There were two instances I remember - she said lemonade came out of the kitchen tap instead of water and when she went to test it, it did. Then she lied to her friend about owning a horse and sure enough there was magically a horse in her garden and it poked its head through the kitchen window.

At that point the teacher shut the book and never read it again and we never found out how or why everything was coming true.

I know it's sounds silly but not knowing the ending has haunted me for years! I'm sure it will be something very predictable like it was all a dream but I just have to find out haha.

Does anyone have any inklings?