It appears that the situation in the UK is not getting any better, especially after a group made a dire warning of an acute shortage of qualified school teachers, especially in physics.
I have mentioned this before that in my experience, many people who grew to dislike physics, usually had a very bad introduction to it, which is highly understandable. It isn't confined to just physics. So having a high school teacher who is teaching a subject he/she didn't specialize in not only might compromise the accuracy of the subject being taught, but also lacking the "enthusiasm" of the person who genuinely is interested in the subject matter. This last part, I think, is what robs of the students the interest in physics.
It is also why I try to highly some of the teachers and instructors who, in their love and enthusiasm for the subject, went out of their way to make physics more interesting, more exciting, and more accessible to their students. These are the most valuable people in the efforts to get more students to take physics classes, and not necessarily major in physics.