Patients are being refused access to GP surgeries because of a shortage of doctors in Brighton and Hove.
Almost all the surgeries in Hove and several in Brighton say they are no longer accepting new patients because they are overstretched.
There are about ten GP vacancies in the city and surgeries are having trouble recruiting more staff.
Portslade Health Centre in Church Road is one of the surgeries forced to close its lists.
GP Susan Rockwell said: "One of our GPs is leaving the practice but we have not had a single response to a national advert we made to recruit a new partner.
"It means the other GPs in the practice will have more people on their lists and we will have to bring in locums to provide cover. It means that we simply can't manage to take on anyone else as well.
"It's not just this area which is having problems. There is a shortage of GPs everywhere.
"Pay levels are part of the problem, especially in an area like this where the cost of living is high, but it is mainly nurses who are badly affected.
"The real problem for doctors is that becoming a full-time GP is no longer an attractive proposition.
"People who are newly qualified look at the long hours and the immense workload and decide to look elsewhere."
Dr Rockwell said morale among GPs in the city was low.
At the moment they are worried about patient safety if they have too many people to look after.
Dr Hamish Meldrum, joint deputy chairman of the British Medical Association's general practitioners committee, said there were problems across the UK.
He said: "It is quite a serious problem and it is something we have been warning the Government and previous governments about for some time.
"The most common reason is when one doctor retires and then a practice cannot recruit another one."
Dr Meldrum said measures such as increasing pay, persuading GPs not to retire early or enabling more doctors to work part-time might help.
The number of GPs per 100,000 people in East Sussex, Brighton and Hove has fallen in the past four years from 53.2 to 51.9. The average for England and Wales is 52.7.
The city is one of several locations across Sussex to benefit from a "golden hello" scheme where doctors are given a £5,000 bonus if they are move into an area where there are not enough doctors.
Worthing and other parts of West Sussex are also experiencing critical shortages.
One of the busiest surgeries in Worthing suffered a setback when three of its GPs resigned, blaming "NHS burnout".
A medical practice in Bognor recently axed 1,500 patients from its list because of a shortage of GPs.
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