I have been trying to remember/find this book on and off for about ten years.
When I was at middle school (mid 90s) I read a book about a community of people who lived in secret tunnels in and around the London Underground. I think it began with a teenager running away from home and ending up joining this secret underground community. I cannot remember anything else about the plot though.
I suppose there is a chance it was written/published earlier than the 90s.
I would dearly love to rediscover this book.
Thanks in advance for any ideas.