Plans to cut the time surgeons spend training could leave many without essential skills, doctors have warned.
It takes years to train a surgeon
The government is planning to change the way junior doctors are trained. In future, they will clock up 6,000 hours before they can become consultants.
This is down from 8,000 hours at present and 30,000 hours prior to 1993, when other reforms were introduced.
Writing in the British Medical Journal, doctors said 6,000 hours of training "may not be enough".
The doctors suggest the reduction in the time surgeons spend training must impact on their skills.
"To become a competent surgeon in one fifth of the time once needed either requires genius, intensive practice or lower standards," they wrote.
The doctors, who included two who are in charge of training surgeons in London, said they were concerned about the government's plans.
"We are left in the worrying situation where 6,000 hours of surgical training in its current state may not be enough to produce these new generalists, let alone provide consultants that can go on to become the kind of specialist consultant surgeon that we take for granted today."
The doctors said recent surveys had found evidence to suggest recent changes were having an impact on surgeons' training.
"The largest ever survey of senior house officers in orthopaedic surgery showed that a third of these trainees were not taught in theatre or clinic," they wrote.
"We cannot rely on highly able and motivated trainees and trainers to struggle on like this. Surgical training must be recognised as a priority."
However, the Department of Health rejected the claims.
"We are working hard to ensure that more structured and better quality training will be available to junior doctors," a spokeswoman said.
"Shorter training for doctors will emphatically not mean lower standards.
"We are working to streamline training by ensuring that all training time is used to the optimum."