Roadside camping in England?

Next summer I will be taking a month to bike around England/Scotland. It is my hope that most nights I could just find a stretch of road outside of a town and camp. For those who have been to/lived in England, is this realistic? Are there strict laws against it, and are the people generally friendly enough to bikers to allow for this? When I'm staying around larger towns, i'll just stay in a hotel, but if i'm out in the country, will camping be an option? Thanks!