A dedicated team of prosecutors is to be set up to investigate rape and other serious sex crimes across Scotland in a bid to improve the country's poor conviction rate for such offences.

Lord Advocate Elish Angiolini announced yesterday the team of specialist Crown Counsel, based at the Crown Office in Edinburgh, would be active in directing criminal investigations from "the earliest stages" as well as providing advice and support to the Procurators Fiscal Service.

The National Sexual Crimes Unit will also include a dedicated team of specialist procurators fiscals.

The shake-up, which was welcomed by Rape Crisis Scotland, comes amid criticism of Scotland's 2.9% rape conviction rate, and is one of several moves designed to improve the way in which sexual offences are dealt with by police and prosecutors.

The new unit is expected to take up cases - including rape, sexual abuse, child pornography, sexually motivated murder and people trafficking - for sexual exploitation.

It follows a shake-up of the Crown Counsel team, announced last month, which included the promotion of Dorothy Bain QC to principal advocate depute, and Derek Ogg QC to assistant principal advocate depute.

Mr Ogg, who has a string of high-profile prosecutions under his belt, will head the specialist team when he takes over responsibility for the lead role on sexual offences in his post, which he takes up in June, replacing Ms Bain.

Mrs Angiolini, who has previously defended Scotland's record on rape convictions, saying the commonly-quoted statistics were "misleading", said that sexual crimes were often challenging.

She said: "Sexual crimes are undoubtedly among Scotland's most disturbing and harrowing crimes. For prosecutors, sexual offences are often the most challenging and sensitive cases to bring before a court.

"However, I am determined that we will continue to do our utmost to bring compelling prosecutions and treat victims with dignity and respect.

"For victims, even the prospect of a criminal investigation and giving evidence in court can be a deterrent to reporting these crimes in the first place. We want them to have confidence that their cases will be handled by specialists equipped to ensure that the prosecution of these crimes is as professional and effective as possible. I look forward to leading the team and building on our existing expertise."

The Crown Office set up its first team of specialist prosecutors in June 2006 to deal with the growing threat of serious and organised crime.

The unit of 30 lawyers, detectives and financial experts were tasked with tackling drug-running, money laundering, serious fraud and seizing the profits of crime.

The latest team has been set up on the back of a review of sexual offences by the Lord Advocate, published in 2006, which included recommendations to introduce specialist training in investigating rape and sexual offences.

The Crown Office said yesterday that all 50 of the recommendations in the report would be implemented by this summer. The new unit was established on the recommendation of Ms Bain, who has recently worked with the Lothian and Borders area sexual offences team to provide advice at the earliest stage in investigations and, as part of her review, visited other jurisdictions to identify best practice.

Sandy Brindley, of Rape Crisis Scotland, welcomed yesterday's announcement.

"Rape Crisis Scotland is supportive of the creation of a National Sexual Crimes Unit. Rape is a crime which can have a harrowing and long-term effect on its victims, and it is one which people can often be reluctant to report to the police," she said.