Government plans for changes in the law to boost rape conviction rates are in disarray after the judges who would have to put them into practice told ministers they oppose them.

The Council of Circuit Judges, the influential body representing all 637 circuit judges in England and Wales, has dismissed all the proposals, including a measure to try to make it easier to convict in cases where the victim was binge-drinking.

The plans are the latest attempt to reverse a plummeting conviction rate for rape that has dropped from 33% of reported cases in 1977 to just 5.29% in 2004. But the judges have rejected all the principal proposals, which include:

• A new statutory definition of capacity to consent to sexual intercourse, which would clarify when a woman can be considered too drunk to make the decision.
• The use of expert witnesses in court to help dispel "rape myths" and inform the jury how rape victims are likely to act. Although this routinely happens in the US, judges here believe their use would cause delays and prove expensive, unnecessary and "inappropriate".
• Showing videotaped interviews with victims filmed when they first go to the police. Ministers said this would bring home to jurors the victims' distress. But the judges are concerned that this would be too emotive and not help establish the truth of the allegations. They argue that some people are particularly good at faking distress.

Overall, the judges believe that the proposed measures are too complex and are urging ministers to have more faith in the common sense of jurors. "The law shouldn't be complicated. It should be something that everybody understands," one circuit judge said.

Their response has left the reforms in limbo. When they were first announced last March, ministers said they hoped to have them in place within 12 months. But no date has been set for publication of the government's final proposals.

The central plank of the consultation paper - Convicting Rapists, Protecting Victims - proposed introducing a statutory definition of capacity to consent to sexual intercourse. The intention was to try to clarify when a woman can be considered too drunk to be able to consent.

The suggestion followed the furore over a rape trial at Swansea crown court in 2005, when a judge stopped the case after the prosecutor said the alleged victim was so drunk that the crown was unable to prove she did not consent to sex.

But the judges say that leaving capacity undefined is "a sensible and appropriate course". One circuit judge told the Guardian: "The line [between capacity and incapacity] is something that is probably best left to a jury to decide on all the evidence. They will hear what the parties say, what happened, and so on. At what point does the law say this person is incapable?

"The trouble with over-complicating things is the more you over-complicate it the less likely it is than anybody will ever get it right. In the long run the average jury of 12 people know when drink means that you're incapable and when it means you're not."

Of the Swansea case, he said: "The judge saw the woman and the evidence, as did the experienced prosecutor. To say later that this has all gone horribly wrong when the prosecution's own representatives decided it was unsafe to try to get a conviction on the evidence is a distortion of the truth. In the end, so far as our law is concerned, these cases are decided by 12 ordinary people."

A Home Office spokeswoman said: "The government believes that the conviction rate in rape cases remains unacceptably low and we're currently looking at a range of options to strengthen the legislation further. We received nearly 100 responses to the consultation representing a wide range of views. All the different points of view will be taken into account when we decide on the best way forward." She said a decision would be taken soon.