For much of his time as Iraqi Prime Minister, Nouri al-Maliki has been criticised for inaction and indecision. The initiative that he is undertaking in Basra can hardly be condemned on either count. In taking the fight to the ad hoc bands of militias and criminals who effectively control swaths of that city, he has put his own standing, the reputation of Iraq's armed forces and his country's renewed claim to nationhood on the line. If he succeeds in restoring order in this part of southern Iraq, displacing the followers of Moqtada al-Sadr in the process, then the prospects of Iraq becoming a stable and prosperous nation would be enhanced substantially. If he were seen to fail, by contrast, not only Basra but sections of Baghdad itself would be placed beyond the command of the central Government. Hopes for permanent peace would thus recede.

It is imperative, therefore, that this mission is a success and not a failure. In ideal circumstances, the battle would be won by Iraqis alone, with the security forces teaming up with tribal elders to overthrow gangs that have exercised ruthless authority on the streets and interrupted national oil supplies for private smuggling and profiteering. This is precisely the course that Mr al-Maliki is attempting to steer and he is right to want to achieve his ends by these means. It is possible that he will prevail but his opponents have the advantage of local knowledge and have demonstrated that they will not be disarmed without a struggle. At a minimum, the effort might require air support from Britain and the US and realistically it could demand yet more firepower.

Such a reverse might be embarrassing but it is far better than the alternative options. It would be little short of a disaster to allow Mr al-Maliki's drive to end in humiliation while some 4,000 British troops sat on their hands at Basra airbase, and it would scarcely be better if the Americans were asked to divert resources from their surge strategy so that UK Forces could avoid a conflict. Britain assumed responsibility for security in southern Iraq at the time of the intervention just over five years ago and it remains best placed to assist the Iraqi Army in its contest today. If it is not possible to rescue Basra before elections are due to be held there in October, that would be a damning indictment of British foreign policy as well as Mr al-Maliki's political credibility.

There are some significant implications to this. As matters stand, the British contingent in southern Iraq is set to be reduced to 2,500 men in the next few months with a further drawing-down in numbers to 1,500 expected not long after. This is partly to allow for a redeployment into Afghanistan but also to send the political signal that Britian's military role in Iraq is coming to an end. In present circumstances, this would mean leaving a total force that was barely sufficient to conduct training of the Iraqi Army and which could be vulnerable to attack in its own base.

It would be irresponsible to stick to this timetable. Ministers should make it plain that the current troop levels will be maintained in the area at least until the end of the year and if a modest increase is required to guarantee that conditions in Basra improve dramatically, so be it. This is a crucial moment not only for Iraq's second city but for the whole quest for normalisation. If the militias are disbanded, free elections are held and the oil industry can function properly then wider political reconciliation in Iraq will be lubricated. Britain could bring about that outcome in Basra. It would be a gross dereliction of duty not to try.