Since the government relaxed the quarantine laws in the UK in 2000, it has been possible to take your pets with you when you travel abroad by obtaining a pets passport.   

For all UK animals travelling abroad from February 28th 2000, it is necessary to acquire all relevant travel documents now required by law, (pets passport) down to the last detail, to prevent the spread of dangerous diseases in to the United Kingdom.  This allows you to travel and return to the UK without having to put your pet into quarantine for 6months.       

To obtain a pets passport cats and dogs must be implanted with a microchip to ISO specifications, at no younger than 3 months old, and then must be vaccinated against rabies with all relevant boosters as recommended by your vet.  All dogs and cats must then have a blood test after 30days and a re-vaccination if they fail the test.  Following this you must wait at least 6months after a successful blood test result before your dog or cat is allowed entry or re-entry to the U.K.  {Unless your pet was resident in the U.K. and microchipped, vaccinated and blood tested before Feb. 28th 2000.}      

Three documents are needed for re-entry to the U.K.

1. The PETS re-entry document issued by a U.K. vet.
2. An official certificate of treatment issued by a vet against a potentially dangerous type of tapeworm and ticks which must be carried out by a vet within 24-48hrs before re-entering the U.K.
3. The declaration of residence which you must complete to declare that your pet has not been outside any of the qualifying  countries in the 6months before re-entering the U.K.

Certain countries including Spain also require an export health certificate, issued in the UK, to allow your pet to enter the country.  Once in Spain pet animals need to retain their pet passport, according to the European Union rules, in order to travel to other countries within or outside the European Union or return to the UK.