HSJ has uncovered further evidence of NHS-funded GP practices in prestigious institutions which are not accessible to ordinary members of the public.

Exclusive arrangements at Buckingham Palace and the fee-paying Westminster and Haileybury schools mean their staff and pupils are able to access bespoke on-site GP services, funded by the NHS.

The practices at Buckingham Palace and at the£26,000 a year Westminster school are able to deny access for the general public through a peculiar definition of their practice boundaries, which coincide precisely with the boundaries of the palace and the school respectively. Practices are only obliged to register patients who live within their boundaries.

Both practices are funded by Westminster primary care trust. They are primarily intended for use by resident staff at each of the premises. But a Department of Health spokeswoman said the practices could register other patients at their discretion. In the case of Westminster school, this includes fee-paying pupils.

The school practice has just 243 patients and the Buckingham Palace practice has 304. There are five other NHS GP practices within 0.6 miles of Buckingham Palace and four within that distance of Westminster school. Neither practice appears on the website NHS Choices, designed to give patients information about their local services.

The practice at the£24,000 a year Haileybury school in Hertfordshire does appear on NHS Choices, but a receptionist told HSJ that only patients "with a connection to the school" could register. A spokeswoman for East and North Hertfordshire primary care trust confirmed this.

The practice has around 800 patients, compared with the average in England of 6,400.

HSJ also discovered information which reveals that the payments each practice receives from its PCT for offering basic patient services are far higher than the national average of£63 per patient. The Buckingham Palace practice received the equivalent of£113 per patient in 2007-08 and is run by the Queen's private GP Timothy Evans. The Westminster school practice received£94 and Haileybury school practice received£73.

The practices benefit from the minimum practice income guarantee, which bases income on historic earnings as opposed to the patient need allocation formula.

Labour MP Andrew MacKinlay said he had made several attempts to ask questions in the Commons about the status of the Buckingham Palace practice, but that parliamentary "deference" meant these had been blocked until HSJ exposed the practice last month.

"It's indefensible that there is... an exclusive GP practice for the royal household. But it's outrageous that they should benefit from the minimum practice income guarantee. That's taking it to absurd proportions," he added.