Community policing, which is at the heart of the Patten Report, cannot be achieved in Northern Ireland unless young Catholics and nationalists join the new police force in sufficient numbers, according to Dr Maurice Hayes.
"They will themselves be the force for change, but only if they join. If they don't there will be no change," he says, writing in this morning's Irish Independent.
Dr Hayes, the former Northern Ireland ombudsman, says the new Police Bill has finally become law "in an atmosphere in which the policing has become lost in the politics and in which the rate of change still remains something of a mystery".
He adds: "The difficulty is the widespread scepticism on both sides of both Mandelson and the NIO, which causes politicians to call out even more loudly for reassurance and to refuse to commit themselves to support anything that it not virtually written in his blood.
"The heart of Patten is community policing, policing which is acceptable to and responsible to the community and carried out by a service which is broadly representative of the communities it serves.
"This cannot be achieved unless young Catholics and nationalists join in numbers and are encouraged and enabled to do so by community and church leaders.
"They will themselves be the force for change. If they don't join there will be no change."
The parties in Northern Ireland seemed to have developed an infinite capacity, once a hurdle had been crossed, of replacing it with another "and so on almost to infinity", he says.