Normally, such complaints should be fully processed by the General Medical Council (GMC) in about six months.

The rise is being blamed on increased public scrutiny of the profession following a number of medical scandals.

The GMC decides whether it is right to allow doctors guilty of misconduct to remain on the medical register.

Doctors warn that the situation could be made even worse by the recent introduction of new disciplinary procedures.

The GMC's "performance procedures" allow doctors to be reported where there is evidence of incompetence, rather than criminal or unethical conduct.

Numbers starting to grow

The new system was introduced in 1995, but it is only now that the number of these type of cases is starting to increase.

Bristol surgeon James Wisheart was struck off for serious professional misconduct

Dr Krishna Korlipara, a GP who helps the GMC screen all the serious complaints made against doctors, said that the current delays were "unacceptable".

"There is a huge backlog, now approaching 12 months.

"The public are not being put at risk, as the GMC can impose interim suspensions before the cases are heard.

"But it is unfair on the doctors, who have to wait so long before having the chance to clear their names."

Currently, there are 100 doctors under suspension awaiting a hearing, and complaints as a whole have risen from 1,000 in 1993 to 3,000 in 1998.

Dr Korlipara said: "Although there is only a trickle of cases from the new performance procedures at the moment, that is bound to increase."

He said the huge rise in complaints was due to more patients being aware of their right to complain in the wake of high-profile cases such as the Bristol heart babies investigation.

More workers brought in

The GMC has brought in extra staff to try to cut the backlog, and is to begin holding hearings in two simultaneous sittings instead of the usual one.

GMC president Sir Donald Irvine said: "We have taken steps to reduce the time that doctors take for their cases to be heard by the professional conduct committee.

"These efforts will, we believe, reduce the waiting time and be fairer to both the public and the profession."

In addition, the GMC is asking the government to give it tougher powers to ban doctors who have been found guilty of the most serious offences.

At present, any doctor who has been struck off the medical register can apply for reinstatement after a set period, although most are turned down.