Hey Yellow, don't take it so personally. It's not just LHR but the NATS culture generally. You may feel frustrated with the trainees but I wonder how some of those trainees feel. Especially those who, after putting in significant effort themselves, choose to leave the business completely.
What I saw going through the system getting on for 30 years ago doesn't seem to have changed much over the years. There are still perfectly capable trainees unnecessarily falling by the wayside. Granted, things are not helped by the licensing and training plan requirements which are also focused in many ways on preventing those that do not fit an idealised profile from gaining the requisite qualifications rather than ensuring a licence is granted when one can demonstrate the appropriate competence.
But the simple fact that you include a flippant comment in your post gives a nod to what's in your mind! Just as my inevitable response clearly indicates what's going on in mine.