THE head of Scotland's prosecution service has warned victims of sexual offences may not be getting justice because of recent legal changes.

Lord Advocate Frank Mulholland told The Herald shifts in the balance of evidence following the landmark Supreme Court ruling on the Cadder case mean the human rights of rape victims may now be breached.

Mr Mulholland also revealed he would be strongly in favour of the abolition of the requirement of corroboration because, when combined with the Cadder ruling, fears were sparked that it let down the victims of sexual offences.

The Cadder judgment by the Supreme Court in 2010 said it was a breach of the European Convention on Human Rights to let an accused be detained and interviewed by police without the right to a solicitor.

After the judgment, the Scottish Government commissioned a review by Lord Carloway and one of its recommendations was the abolition of corroboration.

Mr Mulholland said: "The current law does not serve the victims of sexual offences well. I think there is a real risk that the system in Scotland will fall foul of human-rights laws because the requirement for corroboration, together with the impact of Cadder, has resulted in an imbalance in favour of the accused, particularly in relation to rape.

"The analysis Lord Carloway did was very compelling. Pre-Cadder, rape cases were proved on pure sufficiency – we have the complainer saying she was raped, we have to provide corroboration in relation to the rape, penetration, the intention and the fact it was against her will.

"Recent distress helped corroborate it was against her will. In relation to penetration, in many cases the man would make a statement during police interview saying he had sex but denied rape and that was corroboration of penetration. But as a result of Cadder we find people are not saying anything during interview and not giving that common explanation."

He added: "I agree with the recommendation to abolish corroboration. There is a human rights point in Carloway which no-one has referred to. He says the state has a positive obligation to protect and secure the rights of victims."

Gillian Wade, head of Scotland's national sexual crimes unit, has said she would not necessarily support removing the need for corroboration. She said: "We'd have to be very careful before we did that – it can't be done in isolation."

A new Sexual Offences Act in December 2010 widened the definitions of rape and consent. It was hoped this would boost the number of convictions. But figures last December revealed convictions for rape and attempted rape fell by a third, largely due to Cadder. Mr Mulholland said the Cadder ruling had tipped the system out of balance.

He said: "What is the criminal justice system for? It is for a fair trial in which the guilty are convicted and the innocent are acquitted.

"After Cadder the system is out of balance and has shuffled too much in favour of protection of the accused rather than ensuring a fair trial."