I know that's the case for Time Trials as it's one rider at a time, but I thought that multi person start events needed police sanctioning and I would have thought the police would only allow that on closed roads?
You're UK based and in the bike business, don't you pay any attention to amateur road racing? They don't get closed roads. Hardly anything gets closed roads in the UK, everyone in government is petrified of whingeing motorists. Didn't it take an act of parliament to get closed roads for the TdF in 2007?
Amateur road races typically run on circuits with whatever lead cars and motorbikes the organiser can get together. The police don't take any part other than in not prohibiting the race which, in some districts, they do through lack of sympathy.
We rarely have any road races around here hence my question. The bicycle business is only a very small part of what we do and to be honest I've been more involved with triathlons over the years which vary between open and closed roads, although admittedly mostly open roads. The only mass start events that I've attended around here have all been closed road or on circuits. I honestly think that with all the cars on the road these days and the very dubious ways in which many of them are being driven, that having open road mass start events is a worry.
Incidentally, thank you for the first comment in your post, no I don't pay particular attention to amateur road racing, which is why I was asking the question and hopeful to not receive a condescending reply! Just because I work for a company 'in the bike business' does that mean that I should? My passion is the bicycles themselves. To have a knowledge of all the differing events that cycles are involved in and then considering that the bicycles are a small part of our core business, there simply wouldn't be enough hours in the day.