Asbestos

It is illegal to supply any item containing asbestos for money or free of charge.

Asbestos has to be disposed of at registered sites, which are usually controlled by the local council. The HSE web site contains useful advice - http://www.hse.gov.uk/asbestos/faq.htm

Apart from the illegality of people offering or asking for asbestos, there is the undoubted health risk for those handling the material. Don't allow it on your group.