Just in response to some comments above, I have long been of the opinion undercover police revenue operations are a wonderful gateway to tackling other forms of crime. The initial fare evasion offence gives officers the opportunity to detain and search the culprit. I cannot tell you have many times this has led to the discovery of large quantities of drugs, zombie knives, arrest warrants or immigration issues. I have seen all of the above first hand on many occasions.
I've said this for some twenty years or so on this forum, regarding stings at stations. They
always catch far more than fare evasion - but they are considered expensive and difficult to set up. Some even say they're hard to justify as people think they're taking resources away from other policing measures.
I've always said - you have the criminals literally coming straight to you. It's worth not just BTP, but local police, home office and more to be present and mix the operations up so people never know if and when there will be one. That can help bring anti-social behaviour down too.
Now TfL does do more stings than most, but I am not sure they like the multi-agency operations. The police will likely be hesitant to target certain areas for fear of being accused of targeting certain people, for example.
It is also no longer something only the railway should be funding, but - again - there are going to be people upset that the police might be allowed to roam the public transport network looking for criminals and using them pushing through a gate as justification to start questioning or searching them. I think, personally, that this is valid justification as you can't be accused of profiling people to search - you have grounds based on what you've seen (and recorded on Body Worn Video).