Weston General A&E document used out-of-date advice
Health officials looking at the future of a hospital's A&E department put out-of-date information in some public documents.
The clinical commissioning group (CCG) said a national guideline stated that a hospital like Weston General should have 500,000 people in its patch.
But that guideline is from a 21-year-old Royal College of Surgeons report.
The NHS says there is no longer any national advice about population size - that would be a local decision.
Weston General Hospital A&E unit has been shut overnight for 18 months because it could not guarantee safe levels of staffing and last month the permanent overnight closure became the preferred option of local NHS managers.
'Dodgy data'
The 500,000 figure was in a document from the local clinical commissioning group called Healthy Weston - a case for change.
In that document it said "national guidelines say A&E departments, like those at Weston General, should serve a minimum population of 500,000 people"... which is "significantly more than the 152,000 people it currently serves" - a figure generated by adding up all the patients who are registered at 16 doctors' surgeries within the hospital's catchment area.
Bristol, North Somerset and South Gloucestershire Clinical Commissioning Group said: "This figure is drawn from guidance published by the Royal College of Surgeons.
"Meeting the changing health and care needs of local people is our first priority. We have used various population projections - including tourist numbers and housing development figures, for example - as part of the extensive work underpinning the proposals, and we encourage everyone with an interest to have their say during the course of the consultation."
Richard Lawson from the Save Weston A&E group said: "It is worrying that the CCG should stoop to dodgy data like this while presenting a public face of concern for the health of the public.
"The case for Weston to continue as a District General Hospital remains very strong, and the CCG should therefore revise its plans."
The trust's own website says it serves "a resident population of around 212,000 people", with a further 3.3 million day trippers and 375,000 staying visitors increasing this base population each year.