The Animal Welfare Act

Animal Welfare Act 2006 (Scotland) - Docking
As from 30 April 2007 it will be illegal to dock puppies' tails in Scotland (other than for therapeutic reasons) or to travel across borders to have them docked.  Regulations pertaining to this law will be approved by April 2007.

Animal Welfare Act 2006 (England and Wales) - Docking
As from April 2007 it will be illegal to dock puppies' tails (other than for therapeutic reasons or if a breeder can submit evidence to a Veterinary Surgeon that the dog is of a specified type to be used for work, rescue, armed forces, police, pest control).
Regulations pertaining to this law will be approved by April 2007 by England and Wales separately.  It will not be permissible for docked dogs to be shown at fee paying shows.

After the dates the regulations on exemptions come into force, members of the public should report to their Local Authority any breeders they know whose litters' tails have been removed without the required certification.
Anyone flouting the law can be prosecuted and fined £20,000, possible imprisonment and be banned from keeping animals (which could mean that other animals in their care could also be confiscated.
No-one should buy a docked puppy without accompanying certification to prove that the dog has had its tail removed legally and it is intended as a working dog under the categories listed in the regulations. This Veterinary certificate will be proof that the dog has been docked legally and will be important in prosecution cases.