Ibbotson, Eva. The secret of Platform 13

Ibbotson, Eva. The secret of Platform 13. Dutton, 1998 [0-525-45929-4]
There is a portal on platform 13 in London which opens up to magical land. It only opens every 9 years for 9 days. The books opens with a sitter bringing the magical land's prince as a baby through the portal and he is kidnapped! The land has to wait the nine years to go get the prince. The 9 years pass and two groups are sent through the portal to get the child. When they arrive at the house there is some confusion about the two children living there. There is much adventure and action trying to get the correct child back before the portal closes again. This 231 page book is a fun fantasy/adventure book. You should note that Ibbotson is British and there are plenty of "Britishisms" in the book. I purchased this book because of the reference in the title to a similar platform in Harry Potter.