Doctors' leaders warned yesterday that patients were bound to suffer from a sudden move by the government to introduce the profit motive into NHS general practice for the first time since 1948.

Ministers tabled a regulation to encourage competition between GPs and private firms in providing non-standard services such as vaccination, contraception, cervical screening and home visits outside normal working hours.

Those building up a successful business in these activities will be allowed to sell it for profit to another provider.

The British Medical Association said: "This will drive costs up and has the potential to severely damage general practice, the most cost-effective part of the NHS."

The Medical Practitioners' Union said: "It is tantamount to a trade in patients and is simply abhorrent."

The Department of Health said the regulation was linked to the new GP contract, which comes into force next month.

Since 1948 most GPs have been independent contractors, earning a living from fees paid by the government for treating a list of patients. When they retired they could sell premises but were banned from benefiting financially from passing on their patient lists.

This was done by a rule stopping GPs including a "goodwill" element in their balance sheets to reflect the value of future income from the NHS.

Yesterday the health minister John Hutton tabled a new regulation relaxing the ban. From April 1 practice assets may include goodwill for extra services, but not the core services every practice must provide.