With thanks to @Jono_Kenyon, I was brought to the attention of a rather perplexing article.
As evidence for this, he has looked at the leaderboards of certain Strava segments.
The example on the article, for the segment Millbank (up) does indeed have the top 20 male riders completing the segment at an average of over 30mph. The top 3, which Mr Thomas drew particular attention to, had an average of 34mph. Too fast for a cycle lane, you might think.
I have linked to their wikipedia entries: they are professional cyclists. These three segment times were recorded on August 4th 2013, when the Prudential RideLondon-Surrey Classic race was on, which was a professional event held entirely on closed roads.
I went on to look at the other top 20 times on that segment, and only one of them was not recorded in that race, and that was the slowest one in the top 20, at 31.6mph. That’s still pretty fast, but rather puts the claim that “Speeding cyclists are putting pedestrians and other road users at risk” in perspective. Mr Thomas might as well complain about Formula 1 drivers doing 100mph on the streets of Monaco: the logic is identical.
He goes on to claim that people recording Strava segments are engaging in “compeditive [sic] urban road racing” which is over-egging the pudding, to put it mildly. Whilst some cyclists might use Strava to see how they stack up against other cyclists on the same route, and push themselves to record a faster time, to portray that as racing, is completely ludicrous.
Mr Thomas goes on to discuss a specific video he links to where the cyclist is travelling at an average of 32mph in a 30 limit. Mr Thomas complains that “the cyclist is traveling too fast to be overtaken by any vehicle on the stretch between Vauxhall and Lambeth Bridges”. I must confess I do not understand what point he’s trying to make here. If the cyclist is going at or slightly above the speed limit, then no vehicle ought to be overtaking him anyway. And if he is travelling below the limit, and it is safe to overtake, then he cannot be travelling too fast to be overtaken. Perhaps he is suggesting that only drivers should be allowed to speed? (possible, as surveys consistently report that the majority of drivers are habitual speeders 1)
A further relevant point is that speed limits do not legally apply to bicycles, as they are not a “mechanically propelled vehicle”; the legislation specifically only applies to motor vehicles. That’s not to say that cyclists should feel free to simply ride as fast as they want to: they should cycle at a safe speed for the conditions. However, as a cyclist+rider will weigh only roughly a fifth of a normal car, and therefore the kinetic energy contained will be a fifth of a car travelling at the same speed, a cyclist travelling at 35mph poses much less of a risk to others as a driver travelling at 35mph.
So perhaps Mr Thomas, if he is genuinely concerned about the danger to pedestrians, ought to concentrate his criticism on motor vehicles, which pose by far the greatest danger to pedestrians.
1 RAC Report on Motoring 2015, page 8: “Seven in ten drivers (70%) say they regularly or occasionally break the 70mph motorway limit … percentages admitting to exceeding the 30mph and 20mph limits both being 44%”