Assuming they are maintaining a reasonable distance, it does raise the question, how?
Presumably you wrote that within the confines of some sort of Whitehall bubble – anyone who’s been in the real world for the last 5 weeks knows simply setting a 2m rule is not a magic solution.
1. 2m is an arbitrary number which seems about right, had a little bit of science behind it, and is achievable to some degree. The risk isn’t zero at 2.01m.
2. People don’t/can’t always maintain 2m – they have to pass each other on narrow paths.
3. Some people are not very good as estimating or remembering 2m rule. May not be the cyclists fault but doesn’t mean he isn’t passing on infection if he is infected (and it turns out simply breathing on others is a real mode of transmission).
4. Opening gates, pushing buttons on traffic lights, touching a fence / railing whilst waiting at traffic lights, Etc. probably possible to go for a ride without touching anything but your handlebars but plenty will not.
5. Cycling hard involves breathing hard. If 2m is a limit for normal breathing in a supermarket queue heavy breathing is likely to increase it – all the more so if you open you mouth wide to exhale. Potentially coughing, I’ve seen plenty of spitting over the years.
6. There’s obviously a tiny fraction of people who go cycling who will have some sort of accident that then needs others to come to their aid. Could be mountain rescuers at the trail side, an ambulance crew at the roadside, A&E/minor injuries staff, a dentist, an optician etc.
Let me clear, I’m not in the “Just stay home” camp but I think believing that going for a ride is zero risk to yourself and others is misplaced. It may be very low risk, it may be lower risk than going for a walk on a busy route other people follow, it may be lower risk than going to Tesco for your weekly shop but it is not zero risk.