Colin Smith, the Inspector of Constabulary, told MPs that every recommendation he had made about the force had been acted on. But he criticised the slowness with which it had happened.
"There is excessive caution in introducing change," he told the Commons Northern Ireland Affairs Select Committee. And he warned that the RUC could be "losing some Catholics because one is taking too long" over recruitment procedures.
He clashed with Peter Robinson, deputy leader of Ian Paisley's Democratic Unionist Party, who said Protestants could find themselves losing their jobs in order to "put in a Catholic". Mr Smith replied: "That would be an extremely mischievous and most wicked interpretation."
The Government made the reform of the RUC one of its key confidence-building measures in the peace process and included a bill in Queen's Speech when it came into office last year.
Mr Smith, a former chief constable of Thames Valley police, excepted the present RUC chief constable, Ronnie Flanagan, from his criticism but said: "In the higher echelons of the organisation, there has been a reluctance to take brave decisions and move forward. The tremendous bravery they have shown in the last 28 years should now be translated into courage in leadership."