Keir Starmer QC will step down as director of public prosecutions later this year, the Crown Prosecution Service announced today.

Former human rights barrister Starmer, 51, who took up the post in 2008, has indicated that he will not seek to extend his five-year term of office when it comes to an end in October.

In a statement issued by the CPS, Starmer said: ‘It has been a huge privilege to have led the CPS for the past four and half years. I have enjoyed my time very much and I look forward to continuing to work with my colleagues on the important work of the CPS until my term of office ends.’

Attorney general Dominic Grieve QC said Starmer been a ‘privilege and a pleasure’ to work with.

He said the DPP was ‘not just a formidable lawyer’ but that he had brought ‘sound instinct and humanity’ to his role.

Grieve said: ‘He has led the CPS through a difficult time and leaves it as a more professional and more effective service than he found it.

‘The CPS is now, more than ever, a key partner in the criminal justice system. In my view he has been one of the most successful directors of recent years,’ he said.

Starmer has had to deal with many contentious issues during his tenure, including assisted suicide, victims’ rights, the response to the London riots and high-profile prosecutions following the media phone-hacking scandal.

He has introduced core quality standards within the CPS and a quality assurance framework, while also seeking to implement the 25% cuts to the CPS budget demanded by 2015 under the 2010 spending review.

Following the announcement, a leading criminal solicitor called for the immediate end to appointing barristers to the post of DPP.

All directors since 1987, the year after the CPS was set up, have been drawn from barristers in private practice.

Stephen Parkinson, head of criminal law at London firm Kingsley Napley, said that none had any experience of working within the public sector or any serious experience of management.

He said: ‘The last two directors have had no significant prosecution background at all before their appointment. Yet the core of CPS work is decision-making on which cases to prosecute, and subsequent pre-trial preparation.

Parkinson said: ‘Judges, one of whom usually sits on the appointments board, tend to feel reassured if a member of the bar is appointed – yet this practice should stop.

‘Instead the emphasis should be on extensive, practical experience as a prosecutor, a significant management background, and a deep understanding of the public sector ethos.’

He suggested: ‘There are now a number of people holding senior positions within the CPS who are well placed to take the top job, both in terms of their ability and their profile.

‘It is nonsense and insulting to suppose that they are any less independent than members of the bar. Each of them has carried significant executive responsibility already as a chief Crown prosecutor. They know the job and have the confidence of their colleagues,’ he said.

An advertisement for Starmer’s successor will be published online tonight, the CPS said.