Police forces are still not united in developing a new national intelligence system to prevent a repeat of the Soham tragedy, the chief constables' leader warned senior officers in Birmingham yesterday.
Chris Fox, president of the Association of Chief Police Officers, said there was a point when discussions about how to implement the massive IT project must stop.
The system will allow police to check records held on suspects by all forces in England and Wales, including allegations which never led to charges.
It was a key recommendation of the inquiry headed by Sir Michael Bichard into how Ian Huntley managed to get a job as a school caretaker despite having a series of sex allegations made against him.
Mr Fox was speaking on the opening day of the Acpo annual conference at Birmingham's National Exhibition Centre.
The event, which is now in its fifth year, attracts police officers from all over the world and runs until tomorrow.
Mr Fox said: "At some point discussion has got to stop and we have got to accept what the decision is and that is what we implement.
"We can't afford one force to opt out - everybody has got to opt in."
Mr Fox said he had spoken to several police IT experts who believed they had better solutions to setting up the system, known as Project Impact. An interim system, called PLX, is already up and running.
"If we allow people to opt out, and forces go their own merry way, then we don't have the system we should have which is not acceptable," Mr Fox said.
"I am asking police chiefs to go back and ensure that all their people are working to the common good."
Some forces which may be leading the way in IT might have to be prepared to "stand still" so that other other forces could catch up, he added.
Mr Fox also said the Government's civilian Community Support Officers, which have been opposed by some sections of the police, are starting to improve law and order.
The president said CSOs should not be given additional powers. "If we expanded their powers we would have to increase training and increase the levels of equipment," he said.
"If they exercise their powers they would find themselves giving evidence in court, all of which would take them away from the pavement.
"Their role is to be highly visible in the neighbourhood."
CSOs were introduced by former Home Secretary David Blunkett in September 2002.
They have limited policestyle powers but cannot arrest suspects.
The civilians can use reasonable force for up to 30 minutes to detain offenders until police officers arrive.
Home Office research published in December found only "limited evidence" that CSOs had helped reduce crime and anti-social behaviour.
It also found they were being paid up to £7,000 a year less than police officers.
Last year, the Home Office announced plans to extend the number of CSOs from the current 4,000 to 25,000 at a cost of £50 million a year.
Mr Fox also welcomed Tony Blair's calls for a revival of the value of respect within society.
But he added: "What I don't want to hear is that restoring respect is purely a matter of enforcement and policing, because it has got to enthuse the whole of society, from parenting to schools, youth projects and sport, through to a criminal justice system that sentences people properly."