Water companies in the UK produce some of the best-quality drinking water in the world, thanks to decades spent developing treatment techniques to make it safe and aesthetically appealing.

In recent years raising drinking water standards has been the focus, but with the European Union's Water Framework Directive to be implemented by 2015, attention will move to the quality of rivers and lakes. The directive is "the most substantial piece of water legislation from Europe to date", says the UK's Department for Environment, Food and Rural Affairs.