One of the country's leading health insurers is refusing to accept new customers who live in some areas with large Jewish populations, for "commercial reasons".
Last week, James Green, 29, a commercial property manager from Hendon, north London, attempted to buy health cover from Simply Health but had both a Golders Green and a Hendon address turned down.
The father of three said: "My family and I are all ill with some kind of flu virus. So I decided to get a quote for private medical insurance. A private broker wanted £120 a month for my family, so I called Simply Health.
"I was looking to put my family on their highest cover and the salesperson asked to take my details.
You live in NW4? Forget it!
"But when I gave my postcode, NW4, she explained that the company had the right to refuse customers and that they were not looking for new business from the area from which I was applying.
"So 45 minutes later I called again to speak to a different salesperson and told him I was exchanging on a property in Golders Green, and gave him the postcode of NW11. At first he said they would be able to do the policy, but would check.
"He returned saying he could not give me a policy and didn't understand the reason. He said there had been a business decision about this postcode, which was under review, and was very apologetic."
When contacted by JC reporters posing as applicants, Simply Health again refused to provide insurance.
The areas in which the "applicants" lived were Golders Green (NW11), Hendon (NW4), Stamford Hill (N16), Broughton Park in Manchester (M8) and Gateshead's NE8 district.
Addresses in nearby Belsize Park, London and Swinton, Greater Manchester, were accepted by the insurer.
It is unclear why Simply Health refuses new applicants. There is no evidence to suggest that it is based on the fact that there is a high Jewish population in these areas.
It is possible that there are other areas with no significant Jewish populations which are also barred in similar fashion.
A spokeswoman refused to provide details of what lay behind Simply Health's decision.
She said: "We cannot publish a list of postcodes from which we do not take business. It is business-sensitive information."
According to the spokeswoman, the decision not to accept customers from these postcodes had come into effect in December 2009.
She said: "We have made the decision not to accept new customers from a very small number of areas, as these areas are not commercially viable. We will continue to service our existing customers in those areas."