I know that I’m getting older when flu season seems to come around quicker each year – is it the medical equivalent of policemen seeming younger? Flu vaccinations have become more complicated over the last few years, with different ones depending on age. All the practices I know order their vaccinations very early, but they still don’t seem to get the deliveries in time, which is frustrating for patients and GPs.

Flu vaccinations hit the news last month when a GP surgery sent letters urging patients to have their vaccination done at the GP practice, not the local pharmacy, leading to accusations of unprofessional behaviour and that the GPs concerned were putting money before patient safety.

I can see both sides of the story, and I think part of the problem is a lack of awareness about how GPs are funded. Practices are funded around £80 annually per patient. When you add in incentives such as the Quality and Outcomes Framework that might go up to around £120.

That payment is for all the patient’s primary care needs, including paying for doctors, nurses, administrative staff, heating, lighting and insuring the building, consumables such as printer toner, accountancy fees, and paying a plumber if the sink blocks. Everything except the rent on the building and the IT hardware. It isn’t a huge amount to look after someone for a year and without the subsidy from healthy people who never come to the GP, it would be impossible to run a practice on it.

For the sake of comparison, private GPs might charge £60 for a single 15-minute appointment, and it can easily cost over £1,000 for a year’s worth of medical insurance for a dog or cat. Primary care is good value and the ‘all you can eat’ model of funding saves the NHS a fortune. Many GPs question whether it's sustainable in the long-term, but for now it's what we have.

Set against this background are the fees that we can charge for extra services. If a GP vaccinates a patient against flu, they can claim £10.50 from the NHS. It doesn’t sound like a lot, but that's equivalent to roughly a month’s funding for a patient, so it's a significant payment for a five-minute appointment.

For practices that have a big population of patients who are entitled to flu vaccinations, the payment for giving them is an important part of how the surgery balances the books. If lots of patients from any one practice choose to go to the pharmacy to get their flu vaccination, that is potential funding that the practice won’t be able to receive. They may even lose money, as they have ordered the vaccinations upfront.

Cuts in funding mean cuts in services. I know of practices that are considering cutting some GP time as a direct result of a loss of income from flu clinics, and others who have been left with paid-for vaccines that they can’t use. Some have decided not to offer the flu vaccination in the future, as the cost of staffing extra vaccination surgeries and the risk of being left with unused expired vaccinations is too great.

I haven’t seen the letter in question, but I understand that it implied that the vaccine provided by the GP was somehow superior to that given at a pharmacy. That’s untrue, and I don’t think it's an acceptable insinuation. But we live in times when a lack of funding is driving some GPs to bankruptcy and record numbers of practices are closing as they can’t make ends meet. In that context, asking patients who value their GP surgery to support them financially by having their flu vaccination at the practice doesn’t seem like the worst crime in the world.

Toni Hazell is a GP based in a practice in London