BREEDING & SALE OF DOGS (WELFARE) ACT 1999
The Breeding and Sale of Dogs (Welfare) Act is in place to amend and extend certain enactments relating to the commercial breeding and sale of dogs; to regulate the welfare of dogs kept in commercial breeding establishments; to extend powers of inspection; to establish records of dogs kept at such establishments; and for connected purposes.
Under the Breeding and Sale of Dogs (Welfare) Act 1999, those breeders breeding five or more litters per year need to be licensed.
However, a local authority may still classify a dog breeder as being commercial - and therefore requiring a licence - even if the person breeds fewer than five litters per year, if in the local authority's opinion that person is deemed as breeding for commercial gain.
Breeding and Sale of Dogs (Welfare) Act 1999
http://www.legislation.gov.uk/ukpga/1999/11/contents
The Breeding of Dogs (Licensing Records) Regulations 1999
http://www.legislation.gov.uk/uksi/1999/3192/contents/made
The Breeding of Dogs (Licensing Records) (Scotland) Regulations 1999
http://www.legislation.gov.uk/ssi/1999/176/contents/made