The reason why the United Kingdom did not agree is because the Convention sensibly required signatories to the Convention to ban tail docking. The premier dog association The Kennel Club and other dog associations presumable lobbied Parliament and convinced the government to not ratify the convention (sign up to it) because of the ban on tail docking.
In not agreeing to this excellent document they appear to have allowed the Governing Council of the Cat Fancy (GCCF) to continue breeding flat-faced "ultra-type" or "hyper-type" Persian cats despite the GCCF declaring they would take steps to control this (see below). The selective breeding of the Persian cat to create a short skull and nose is referred to in a resolution of experts that is based on the Convention. The resolution sets out breeding guidelines. They say that the flat face is something to be avoided in breeding. That is obvious to most people from the point of view of health issues but it is nice to see it stated at a high political level.
It is disappointing to note that the UK, a country seen as a nation of animal lovers, failed to sign up to a agreement that protects animals. People don't in general know about this fundamental failure. We have to ask whether the British really are animal lovers.
At Article 5 the Convention refers to the vexed question of ethical breeding. The eurocrats have done something very good here. They have decided that sometimes breeders of purebred cats and dogs breed to extreme when over focusing on appearance to the detriment of health.
Here is Article 5:
Any person who selects a pet animal for breeding shall be responsible for having regard to the anatomical, physiological and behavioral characteristics, which are likely to put at risk the health and welfare of either offspring or the female parent.
In short and in layperson's language: when breeding cats and other animals there should be a concern for the cat's health and behavior. Common sense. The Convention simply requires responsible breeding.
As a consequence of the Convention and resolution the GCCF agreed in a declaration (March 1995 - almost 20 years ago) that they would "take necessary measures to control the breeding of animals with genetic or phenotypic characteristics harmful to the welfare of the animals in order to prevent suffering of such animals.."
You only have to see the Persians on their website today (May 2012) to conclude that the GCCF still support the breeding of extreme Persians. Can someone tell me why? Have I missed something?