If you are in any doubt as to the legal status of drugs you are carrying, you are advised, upon arrival, to declare them in the Red channel. The United Kingdom has severe penalties for drug smuggling. Drug traffickers may try to trick travellers. If you are travelling to the United Kingdom, avoid any involvement with drugs. Never carry luggage or parcels through customs for someone else.
Animals can carry disease, especially rabies.
The UK is currently rabies free. All pet animals entering the UK must have a current import licence and undertake six months' quarantine at approved quarantine premises. There are no exceptions and any illegally imported animal is liable to be destroyed. The law is, however, currently under revision. Subject to a successful pilot scheme, from April 2001 dogs, cats and some other species coming from the EU and certain other countries and rabies free islands will be allowed to enter the UK without quarantine, provided they meet certain conditions.