The UK registered charity, Sustrans, has created the brilliant National Cycle Network for the whole British Isles. As well as being a great way to travel and good for your health, the growing Network makes an important contribution to improving the environment, and also helps you have more possibilities to reduce your carbon footprint. Cycling on the Network is on a mix of on-road and traffic routes.
Go to the Sustrans website : all the information you need is here! The website also has a huge Resources section, which includes links to all the main bicycling organizations in the UK, and also similar cycling and environmental projects to be found in Europe and beyond.