Cycling in the time of Corona

A single one-way lane would be a vast improvement, removing it's attractiveness as a rat run.

Er ... no. Quite the opposite. One-way operation would make everything far, far worse. It would attract much higher volumes of motor traffic and cause a huge increase in crashes. There would then be attempts to remedy this situation by introducing traffic lights everywhere until, decades later, the authorities would still be very reluctant to return one-way systems to two-way, a situation we still have all over London. Seriously, one-way systems have been tried and tested all over and they have massively failed (even by the intentions of those who introduced them).

The main thing to understand about drivers is that, while they may get annoyed about detours like anyone would, the main consideration for them is the time it takes them to get from A to B, and of course their expectation of the time it will take. People who ride bikes are more concerned with the distance they have to cover. I call that time-sensitivity and distance-sensitivity, respectively. That's why one-way systems are so bad for cycling; if people don't have proper permeability ('maximum route choice, minimum diversion'), they will cycle much less. Perhaps you're thinking a little like a cyclist in this instance.

It may be counter-intuitive to think that in a place like Richmond Park the long detours (as a result of its shape) caused by a one-way system would not make it less attractive to drive through. Perhaps it would, at times, but the main effect would be a huge increase in motor traffic capacity (caused by less turning conflict at the junctions), a greater perceived ease of driving (one of the early claims for one-way systems was that it would make everything safer as the operation of junctions in and on the perimeter of the system would be simplified so much; this didn't exactly work out), and, as mentioned, much worse conditions for walking and cycling.

Some people think that with one-way systems you can go for contraflow operation for cycling, but that only really works well in minor streets. The problem points in one-way systems are always the junctions.

So, no, definitely don't go for that, I say. The issue with Richmond Park, as with Regent's Park, is that the former carriage drives, which have been incorporated into the walking-and-cycling-only environments in most other London parks, are still available for driving carriages. This is a difficult thing to manage, as certain carriages, for instance those of the (very few) people who live in Richmond Park, or the tourist buses for London Zoo in Regent's Park, still need to be driven there. In Richmond Park, a permit system is perfectly feasible but would need staff to run it and to prevent tailgating, etc., whereas in Regent's Park off-peak restrictions are certainly possible, as previously mooted, but which also pose problems that need funding to overcome.

With sagas like these, there are always reasons why they've been running for so long.