Race watchdogs are hampering efforts to tackle racism inside Britain's jails, the director general of the Prison Service is to claim.

In a speech to prison officers on Friday, Martin Narey is expected to accuse the Commission for Racial Equality (CRE) of hostility towards the service.

He will say a 30-month investigation by the CRE has dragged on for far too long and the Prison Service is being prevented from learning the true extent of racism.

Attacking the investigation in the Guardian newspaper, Mr Narey said: "It's not been about searching for the truth.

"It's been about pinning you to the wall."

'Disappointment'

The unprecedented attack was due to be made when Mr Narey gives the annual Perrie Lecture at the Prison Service training college.

Martin Narey is 'disappointed' by the CRE's enquiry

He will express his disappointment that the Prison Service has not received more help to tackle racism from the CRE.

The official watchdog began its inquiry after the murder of 19-year-old Zahid Mubarek by his racist cellmate at Feltham Young Offenders Institute in March 2000.

The investigation began in November 2000 and has focussed on Feltham, Brixton prison in south London and Parc prison in south Wales.

Mr Narey said: "It should have been brought to a conclusion ages ago and we should have been working with them to put things right."

National Front

In the past Mr Narey has repeatedly recognised that the service is institutionally racist.

He blames the problem on a minority of blatantly racist staff.

The service is the only public organisation to sack staff for membership of the British National Party or National Front.