What does a private GP do that the NHS doesn't?
The usual answer to this question is same-day appointments, longer consultations, home visits, and faster referrals. That answer is true and it is also shallow, because it describes speed rather than medicine. Every item on that list is about getting to a doctor sooner, and none of them is about what the doctor then does.
Here is the real answer. The NHS is built to treat illness, and it does that well. It is not built, funded, or staffed to manage health across a decade, and no amount of effort inside a ten-minute appointment changes that.
What the NHS does better than I do
I want to be honest about this, because I work in it. If you are seriously unwell, the NHS will out-treat any private GP in the country. Emergency medicine, cancer care, surgery, and the machinery around a crisis are genuinely excellent, free at the point of use, and available to everyone. If something cannot wait until morning, call 111. If someone is seriously unwell, call 999. That is not a caveat. That is where the good care is.
Its general practice is also better than its reputation. The clinical decisions made in ten minutes by NHS GPs are, on the whole, sound. The system around those decisions is what has failed.
Continuity
Twenty years ago, your GP knew you. Now most patients see whoever is available, which means the doctor starts every consultation from zero. That is not laziness, it is arithmetic. A partner covering three thousand patients cannot hold three thousand histories.
Knowing a patient is not sentimental. It is clinical data. I can tell you which of my patients minimises symptoms and which catastrophises, which is worth more diagnostically than most tests. I know how your child looks when they are well, so I know what it means when they don't. Losing continuity did not make general practice less pleasant. It made it less accurate.
Trend data
The NHS records your results. It does not, as a rule, read them as a line. A blood test that comes back inside the reference range gets filed as normal and nobody looks at it again, even if it has moved in the same direction for four years. There is no clinician whose job it is to notice, because there is no time in the day where that noticing would happen.
Proactive medicine puts that job at the centre. Your results get read against your last set, not against a population. A number drifting the wrong way across three tests is an early warning. A single normal result is nothing at all.
Time
Ten minutes is enough to deal with one problem competently. It is not enough to take a full history, examine you properly, look at your trajectory, and decide what to do about the next decade. So the system deals with the problem in front of it, over and over, which is exactly what it was designed to do.
A long appointment changes what is possible. Not because I am cleverer in a couple of hours than in ten minutes, but because the questions you can ask are different. Nobody discovers that your father died at 54 in a ten-minute appointment about a sore shoulder.
What that actually changes
Same-day access gets you a doctor faster. Continuity, trend data, and time get you a different kind of medicine, one that acts before you are ill rather than after. If you are choosing a private GP on how quickly they answer the phone, you are buying the wrong thing, and you will pay a premium for a slightly faster version of what you already have.
Ask instead who books your reviews, who reads your results against your last set, and who calls you when something moves. If the answer is nobody, that practice is selling access. Access is worth something. It just isn't worth what prevention is worth.