Michael Howard has turned the spotlight on the CV of the new head of the Crown Prosecution Service.

Ken Macdonald QC's appointment as director of public prosecutions last week was slammed by the Conservatives as an example of New Labour's "rampant cronyism".

Macdonald was a fellow founding member of the Matrix legal chambers with the prime minister's wife, Cherie Booth.

But the Tories were careful not to criticise his qualifications for the role.

However on Sunday the shadow chancellor upped the ante in the Conservatives' opposition to the appointment.

Howard, himself a QC, claimed Macdonald was unqualified for the role having never prosecuted a "significant" case in his legal career.

He told the BBC his evidence made the decision even more embarrassing for the government.

"The fact that he is a close working colleague of Cherie Blair does not disqualify him from that job," Howard said.

"What that does mean though is that you should scrutinise pretty closely his credentials for the job.

"If you engage in that kind of scrutiny you discover that this is a man who has no experience of prosecution at all.

"He has never prosecuted a single significant case in his career."