West Yorkshire Police's Chief Constable is writing to every ethnic minority officer in the county to reinforce his stance against racism.

The move is part of a raft of measures in the wake of a damning television documentary exposing racist behaviour among recruits from other forces.

Colin Cramphorn said he was disgusted by the actions of some rookie officers featured on the BBC's The Secret Policeman and stressed that, although West Yorkshire recruits were at the same training centre featured, none was involved in the controversy.

In a report to the West Yorkshire Police Authority, Mr Cramphorn said: "Particularly over the last decade, there has been enormous energy expended on building trust of the police among minority ethnic communities. The conduct shown on that programme has done immeasurable damage to that trust."

He added: "We recruit from a cross section of society. Unfortunately, our recruitment processes cannot screen out all of the cross-section of ignorance and bigotry which feeds racism in society."

Although "respect for diversity" features seven times during training, Mr Cramphorn conceded there was no test to root out racism among those who concealed it.

As well as a national strategy to tackle the problem, including a complete overhaul of the Association for Chief Police Officers' diversity strategy, West Yorkshire Police was taking its own additional steps, said Mr Cramphorn.

These include personal letters from the force and the Chief Constable to all ethnic officers "to provide reassurance" and to clarify their reaction to the programme.

A "strongly worded" message is being circulated to officers reinforcing the availability of a confidential 'whistleblower' phone line to report racist behaviour.

And an assistant chief constable will brief every intake of recruits on the both the importance of avoiding and reporting racist behaviour.

Inspector Raham Khan, chairman of the West Yorkshire Black Police Authority, said he had contact with about 300 ethnic minority officers and added: "I have not been made aware of any problems."

Insp Khan said the authority took various steps to tackle racism and was encouraged by Mr Cramphorn's pledge to take "positive and swift action" against any offenders.

He suggested that members of the national Black Police Authority be posted at force training centres to reassure ethic recruits and act as a contact point for others.