PETS was originally introduced for the benefit of animals entering or returning to the United Kingdom from other European Union countries, since historically the UK had very strong controls to safeguard against rabies including a compulsory six-month quarantine period on imports of many animals. On 1 October 2001 several European Union countries introduced the PETS scheme, under which animals from any member country may freely travel (with the correct procedure) to any other member country on approved carriers. Over time the scheme has rolled out to other countries such as the United States, Canada, Australia and New Zealand.
- Tapeworm treatment – (dogs only): before entering the UK, all pet dogs (including assistance dogs) must be treated for tapeworm. The treatment must be administered by a vet not less than 24 hours and not more than 120 hours (1–5 days) before its scheduled arrival time in the UK. (There is no mandatory requirement for tick treatment. No treatment is required for dogs entering the UK from Finland, Ireland or Malta).
- Prohibition on the transport of dogs and cats in the passenger cabin, or as baggage - British law precludes all animals entering or departing from the UK either in the cabin or in the hold as 'excess' or 'checked' baggage. Unlike the UK, most western countries do allow airlines to carry dogs/cats on flights provided that specific requirements are met regarding the container the pet will travel in. All animals (except guide dogs) travelling to or from the UK must travel in the hold as manifest cargo. Most airlines do not offer cargo services to individual passengers directly and specialist agents must be used.