Leading article: Mr Reid will need all his skills to tackle this chaos

John Reid has a testing week ahead of him, to put it mildly, with a brand new sex-for-asylum scandal unfolding at Lunar House just before he is due to appear before the Commons select committee on Tuesday over the release of foreign prisoners.

As the Home Secretary can scarcely have touched the top of his in-tray, it will be too early for MPs to call for his head for either of these affairs or for a third disaster - the branding of 1,500 innocent young people as criminals by the Criminal Records Bureau. But he will need to be seen to doing something soon about his shambolic department if confidence in his reforming powers is not to ebb away.

It is questionable, of course, whether any minister, however tough, can make a lasting impact on such as vast, inchoate empire as the Home Office, in which the separate directorates, such as prisons and immigration, hardly seem to talk to each another.

The blame for this incoherence belongs partly to Tony Blair, who failed to break up the Home Office into manageable units early on. Mr Blair considered doing just that years ago, but backed off when the then Home Secretary, David Blunkett, made it clear he did not want his fiefdom downsized. That was a mistake, as the creation of a separate justice ministry, relieving much of Mr Blunkett's burden, was and remains a sensible idea. Another opportunity for reform presented itself when Charles Clarke was sacked, but again nothing transpired as Mr Blair wanted the latest brushfire put out without delay.

Given that Mr Blair has passed up the opportunity to reform the Home Office by hiving off some of its more significant functions, Mr Reid is probably the best man available for a nigh-on impossible job.

His reputation as a bruiser will help in a ministry where a bit of brutality is called for. For a start, he needs to make prison and immigration officials communicate properly. Mr Reid's bruiser qualities should also come in handy with Number 10. The Home Office has got to stop allowing its priorities to be set by Government targets. Mr Clarke got into a mess when he allowed senior officials to become so preoccupied with meeting Mr Blair's demands that they dropped everything in order to cut the number of asylum seekers. With his eye on newspaper headlines, the Prime Minister was obsessed with ensuring that removals finally outnumbered the number of unfounded claims, disproving Tory assertions that asylum was "out of control."

When the Home Office more or less met that goal, no one noticed - as by then it was up to its neck over the release into the community of foreign prisoners. If Mr Reid can persuade Mr Blair to let the Home Office sort out its problems without reference to tomorrow's headlines, he will be doing his department a favour.

Finally, Mr Reid needs to take Lunar House in hand. The Immigration Directorate has become a byword for chaos. The calibre of many of its officials is so dire that few will be surprised by reports that an immigration officer may have targeted a young asylum seeker and offered to "help" her case in a highly questionable manner.

The Home Secretary needs to do more than get rid of a few bad eggs. He has to bring in more top-calibre officials and stop the dizzy-making turnover in staff who tend to flee Lunar House as if it were a plague zone.

Asylum and immigration is fast becoming an issue that floats more or less permanently near the top of voters' concerns and thus of government, too. The overhaul of the Immigration Directorate, along with the allocation of far greater resources, needs to be at the centre of Reid's action plan.