John Reid’s statement to the House of Commons on Britons convicted abroad was designed to show that his department’s latest master class in institutional inertia would not be repeated, and to reassure the public that any risk it posed to the public was being minimised swiftly. It failed on both counts. The core of the emergency that has consumed the Home Secretary’s attention for the past 48 hours is a list of 280 names of serious offenders at liberty in Britain, some of whom could be working with children and vulnerable adults. Little more is known about them; too little, at any rate, to enter their details in the Police National Computer (PNC), where prospective employers could screen them with the help of the Criminal Records Bureau. This much Mr Reid admitted. But he also sowed confusion where he claimed to be bringing clarity.

He sought to blame, in part, the “patchy” implementation of a Council of Europe convention on mutual legal assistance under which details of convictions of Britons for foreign crimes were sent to London voluntarily until last year. Implementation may indeed have been patchy. Yet it still produced 27,000 files. All of these gathered dust in the Home Office until last May, and most proved detailed enough when finally studied by the Association of Chief Police Officers (Acpo) to enable it to categorise offenders by the seriousness of their crimes.

Mr Reid further sought to spread responsibility for the controversy by insisting it had been brewing since the Council of Europe convention came into force in 1959. Yet one of his junior ministers, and his Prime Minister, admitted that the vast bulk of the 27,000 files accumulated between 1999 and 2006.

It is entirely plausible that the quality of information in many of these files is thin, and Mr Reid must be held to his promise to commit the resources required to obtain full dossiers from the relevant foreign governments on the 280 serious offenders still not listed on the PNC. It is also clear that much of the backlog now being processed by Acpo built up during David Blunkett’s tenure at the Home Office, during which Sir John Gieve was his Permanent Secretary. In the same period, the department’s finances spiralled out of control and the seeds of the crisis that eventually unseated Charles Clarke as Home Secretary — the failure to deport foreign criminals on completion of their sentences — were sown.

There is little doubt that Mr Blunkett presided over a department in which senior civil servants too often suppressed or neglected intractable bureaucratic problems. More alarmingly, Mr Reid has either exaggerated his own success at transforming the management ethos of a vast organisation he famously condemned as “not fit for purpose” on taking over eight months ago; or it was in even deeper chaos then than he supposed.

Mr Reid assured David Davis, the Shadow Home Secretary, that he repeatedly required his senior team to alert him to potential failures in the massive data-processing schemes on which public safety in the digital age depends increasingly. Why, then, did it take Acpo and the House of Commons Select Committee for Home Affairs to draw his attention to this fiasco? He is right to order an inquiry to answer this question. He would be very wrong to suppose it will absolve him of his own share of responsibility.