It never was about pay. Before the 2025 pay rise, F1s were paid on average £43,275 p.a., and F2s £52,310. Medicine and dentistry are unequalled among university subjects for salary and employment prospects after graduation.
Nor is it in reality about training posts or foreign competition, although it has certainly been sold in that way. The intake of foreign doctors and the mismatch between graduate numbers and training posts, as opposed to non-training posts, (the BMA refers to training posts but more than half of F2s choose not to apply for this specific type of post) are responses to a historic problem with retention.
We will soon have 15,000 UK doctors graduating each year but only 2-3000 consultant or GP jobs for them at the end of their training. You may think there should have been a better way of setting about this problem than adding fuel to the fire, but Mumsnet threads on entry to medicine show how popular it has been. When you have teachers telling you that "it doesn't matter which medical school you go to or what sort of 'teaching' you will get there, a doctor is a doctor the GMC makes sure of that," and medical schools are more than willing to prioritise DEI over academic ability and lay on courses that don't include pesky scientific stuff, medicine is seductive - up to a point.
Doubling medical school places without a commensurate increase in GP and consultant numbers obviously has a worsening effect on retention, and it cannot be fixed simply by creating more training posts. Given that the focus of the BMA is on unreal and pointless issues it looks very much as though the leadership are just whipping up bad feeling to advance their medico-political careers.