Free Places to park overnight

I hired a large motorhome in which to spend four weeks travelling around the UK, starting from London and heading north to Scotland, then down to Wales, and finally covering the lower part from Cornwall back to the New Forest in Hampshire before returning home to London. In the four weeks we only spent about six nights in actual campsites.
The first day was spent travelling on the motorway up the M1, A1 etc., with no sign of a camping spot for many miles, paying to park in the lorry park section of a service station would have been very costly, so we looked around for somewhere free to park, it was getting really late and luckily for us a nearby lorry driver on CB radio told us where to stop. The darkened parking area of a large industrial estate was ideal, and we tucked ourselves into a corner out of the way, it was actually quite a friendly little 'one-night community', drivers sitting around outside in the warm summer night chatting over a hot drink and quick meal cooked over a primus stove.

Industrial Estates can be a great place to stop with a camper, even more so with a stealth camper. As long as you arrive late, leave early, and do not park in a way that it interferes with any articulated vehicles turning, delivering or prevents them from parking. Always check first that there are no signs prohibiting overnight stopping or specifically states 'No Camping or Caravans'. Also check that it doesn't have security officers patrolling the parking area, and always be prepared to move on if you are challenged.