Outside peak hours they are allowed on the sub-surface lines (Circle etc) as those have larger trains and simpler emergency evacuation.
It's still not something you'd want to do very often. I think I did it once with a new bicycle that I'd bought from the other side of London, where the route home would have been long and completely new to me.
It's still not something you'd want to do very often. I think I did it once with a new bicycle that I'd bought from the other side of London, where the route home would have been long and completely new to me.
Map of allowed lines: https://content.tfl.gov.uk/cycles-on-public-transport.pdf