Hi, Rusty!
Yes, it seems to be cyclists in the amateur race that were involved in the crashes.
The first crash requiring three air ambulances apparently, according to the computer news, although it only mentioned one person being seriously injured.
And the second incident that happened later, only the one air ambulance.
The events certainly seem to be well organised.
I don't like watching a sport where there is a strong likelihood of (serious) injury though.
I can derive no pleasure from the sport, as I am always "waiting" for the next disaster.
I'm edgy all the time!
You mention Regent's Park being big! We have so many parks both in Central London and out in the 'suburbs'. Many of them are very large indeed!
And we have a lot of commons too.
London and its surroundings are very green!
Thanks for all the updates and links, JG!
It is very helpful.