Image copyright HM Chief Inspectorate of Probation Image caption Paul McDowell said it was "imperative that any inspectorate is independent and seen to be so"

The chief inspector of the probation service in England and Wales has resigned because of a "potential perceived conflict of interest".

Paul McDowell's decision relates to his wife's role as a senior manager at Sodexo, which has taken over the management of a number of probation contracts.

Mr McDowell said it was "imperative that any inspectorate is independent and seen to be so".

He took up his role in February 2014.

Payment by results

Sodexo, in partnership with crime reduction charity Nacro, has been selected by the Ministry of Justice to run six of 21 probation contracts.

Under the new probation scheme, which started on Sunday, private contractors will rehabilitate prisoners who have served short sentences.

The companies will be paid by results and earn more money if offenders do not commit further crimes.

Mr McDowell said in a statement: "Although we have measures in place to manage any conflicts of interest, and I would always carry out my duties without fear or favour, it is clear that a perception of conflict around my post remains."

Before becoming chief inspector of probation, Mr McDowell was chief executive of Nacro and a governor of HMP Brixton.