By Ray Dunne
BBC News Online health staff in Llandudno
The NHS could carry out thousands of extra operations each year if doctors already in the UK were allowed to treat patients, it has been claimed.
There are 12,500 staff and associate specialist doctors in the NHS
The NHS employs over 12,500 staff and associate specialists.
These are experienced doctors, but rules on medical training mean they are not allowed to become consultants.
Doctors at the British Medical Association's annual conference in Llandudno said the rules stopped them from doing extra operations.
Most staff and associate specialists are from overseas. Many are highly experienced.
But because they did not work their way up through the medical training grades, they are not eligible to become consultants.
Many say they do the same work as consultants, without getting any of the recognition or financial rewards they deserve.
They also say that the rules prevent them from treating as many patients as they otherwise could.
Since they are not consultants, they are not able to run their own clinics or have their own patient list, which means they can carry out operations on them.
The doctors say the current rules hurt them and patients.
"Patients are losing out because highly skilled specialists are being prevented from offering their full expertise," said Mohib Khan, chairman of the BMA's staff and associate committee.
Vijay Kumar, one of the doctors stuck in this grade, say they could help to cut NHS waiting times.
"It's frustrating that so many patients waiting for operations are being sent overseas, or to independent sector treatment centres staffed by surgeons from countries like South Africa.
"I fail to understand why they can't be treated by someone like me."
Mr Subhash Halder, an associate specialist in Halifax, said he has had to refuse to operate on patients because he cannot become a consultant.
"I was getting referrals from different hospitals nearly every month, but I couldn't admit any patients under my own care.
"They had to be admitted under the care of a consultant, even though I did the operation, I did the follow-up and I got the results."
The BMA conference also heard calls for the NHS to make better use of refugee doctors who were in the UK but were not allowed to work.
"There are doctors working as dustbin men and others because they cannot get on the medical register," said Rae Martin, a surgeon from Cambridge.
Dr Edwin Borman, chairman of the BMA's international committee, said work was being done to try to help these doctors.
However, he acknowledged that more needs to be done. "We should help them," he said.
Dr Sam Yerington, deputy chairman of the BMA, said it made financial sense to try to bring refugee doctors into the NHS.
"It costs £10,000 to train these doctors. It costs £250,000 to train other doctors," he said.
"We desperately needs these doctors and their experience."