The AIP is the Aeronautical Information Package, or 'Air Pilot' which gives every possible piece of information about civilian flying in this country.
'Pooley's Flight Guide' is a book which is basically a basic copy of the same information. both have the published contact numbers of every ATC tower in the country.
have a look at
www.ais.org.uk for the AIP online version. Doesn't cost anything to register.