The UK really was once the dirty man of Europe. We had the highest level of sulphur dioxide emissions in Europe, resulting in acid rain that devastated Scandinavian forests. Our seas were akin to open sewers as we pumped human effluent in them as part of a "dilute and disperse" approach to pollution – the result of which I vividly recall from family holidays. And our drinking water was contaminated with a cocktail of chemicals.
British politicians consistently used the mantra of "sound science" as an excuse to dither and delay, often only taking action when incontrovertible damage could be proved – and sadly, in many cases, already done. This backward, discredited approach to policy making – which proved so damaging in the case of BSE – is still favoured by many UK politicians and civil servants, as demonstrated by the government's refusal to back recent EU restrictions on neonicotinoid pesticides linked to bee decline.
The EU's approach to policy making is fundamentally different. Informed by the precautionary principle, and institutionalised within the environmental provisions of the Lisbon treaty, it requires that laws be introduced if there's a potential risk to human health or the environment – at least until evidence demonstrates otherwise. This is an approach – largely due to the efforts of our more progressive continental cousins in Scandinavia, Germany and the Netherlands – that is still not properly understood by many UK politicians and civil servants (as George Monbiot explained recently).
As a result we enjoy cleaner drinking water, cleaner bathing beaches, and cleaner air. The laws that gave those benefits to us were strongly resisted by the UK government.