In 1977, a third of those prosecuted for rape in England and Wales were found guilty and punished.

In the intervening three decades much has been spoken and written about the crime of rape.

The law has been made considerably tougher and public awareness increased.

Women making allegations of rape can expect much better treatment from the police.

Judges are also less likely to allow intrusive and over-aggressive questioning from defence lawyers.

And what has been the result?

By 1999 only one out of every thirteen alleged rapists were convicted. And by 2004 the conviction rate was down to one in 20.

Complaints rocket

And that's not all.

Nearly every country in Europe convicts a higher proportion of people accused of rape than Britain.

Of course, it's not as simple as it seems.

" The idea is to challenge prevailing attitudes about how women who have been raped should behave, both in court and in their dealings with the police " Rape trial video plans

The main reason why conviction rates are falling is that the number of people reporting sexual violence is rocketing.

They think they will be treated sympathetically and their allegations taken seriously.

It's an important achievement for which the government, the police and others can rightly take credit.

But what rape victims probably don't realise when they take the momentous decision of making a rape accusation is just how unlikely it is that their attacker will end up in jail.

The Crown Prosecution Service, which has reformed its own procedures in rape cases, now initiates more prosecutions.

But juries remain stubbornly resistant to convict.

Expert witnesses

So will the government's proposals today have any effect?

The idea is to challenge prevailing attitudes about how women who have been raped should behave, both in court and in their dealings with the police.

" The government denies that its proposals would affect the overall burden of proof "

An Amnesty International survey recently said a third of respondents thought women who behaved flirtatiously were wholly or partly responsible if they were raped.

But if the prosecution is allowed to call expert witnesses on trauma and other psychological effects of sexual violence, perhaps the defence ought to be able to call its own witnesses.

Which might leave the jury just as confused as before.

And one difficulty of allowing taped police interviews to be played in court is that the first "live" evidence a woman gives might be when she is being cross-examined by a hostile defence barrister.

Not an easy start for someone having to re-live such a traumatic event as rape.

Extra dimension

The government denies that its proposals would affect the overall burden of proof.

But it knows that it has to tread carefully.

Rape is an especially difficult crime because most attacks are carried out by someone known to the victim and there is often no useful physical or forensic supporting evidence.

It is one person's word against another.

But there is a further dimension that rape support groups have been stressing.

Sexual violence is thought to be hugely under-reported, with only an estimated 15% of incidents coming to the attention of the police.