Another minister is brought in to tackle the demanding construction portfolio. But how long will Margaret Hodge have before she's moved on, too?

Government reshuffles always have to satisfy a number of objectives. In part they are about political management - finding slots for people that the prime minister wants to include in their team. This cannot always be reconciled easily with the other objective of getting people into jobs that they are best equipped to perform.

So John Reid has, in his own words, moved effortlessly upwards through eight separate jobs in as many years. He is now tasked with turning around the deep-seated problems of the Home Office - described as dysfunctional by his predecessor. It is difficult to see how a fundamental transformation of such a large and accident-prone department can be accomplished within one year - which, on past performance, is the likely duration of his tenure. It also removes him from the Ministry of Defence, a department to which by common accord he was particularly well suited.

Similarly, it is all change for the ministers to whom the construction industry relates most closely.

Alun Michael is dropped after just one year. In his place comes Margaret Hodge, who would be the first to admit that she will have a steep learning curve to ascend in the months ahead.

I have known and worked with Margaret for many years. I like her and have a great deal of respect for her energy and intelligence. I have absolutely no doubt that she will work hard to get on top of her brief and engage constructively with the industry. But it will not be easy. The relentless merry-go-round of ministers makes it desperately difficult to build long-term constructive relationships and develop an understanding of the challenges facing the industry. This is essential if ministers are not to be wholly dependent on advice from their civil servants as to which are the priority issues on which they should focus and how they should approach difficult decisions.

Margaret Hodge would be the first to admit she has a steep learning curve in the months ahead

A detailed understanding of how the industry works and relates to the arms of government is particularly important in the case of construction. For not only is the industry itself complex, with a plethora of different bodies speaking for particular interests, its interfaces with government are equally diverse. So the minister for construction in the DTI needs to work closely with colleagues in many other spending departments whose policy and procurement decisions have huge significance for the industry, as well as, of course, the Treasury, which has the biggest impact of all. Maintaining that network of contacts across government as well as making sense of messages and pleas coming from all sectors of the industry is itself a challenging task, and is made no easier by the reshuffle that will come when the prime minister hands over power to his successor.

There is one further malign consequence of frequent changes of minister. Each new office holder wants, perfectly naturally, to make their own mark. So there is an inevitable temptation to launch new initiatives or to announce eye-catching changes in policy. The constant chopping and changing of ministers, policies and initiatives is frankly difficult to reconcile with good management of the portfolios. Most businesses would look aghast at the process by which what is supposed to be the organisation's senior management team is put together. It is certainly damaging in those areas where continuity and consistency are essential to delivering the necessary outcomes. Yet probably the greatest challenge for the government is to ensure effective implementation of a number of established policies that need to be followed through.

This is certainly true in the case of construction where the reform agenda set out over the past decade by the Latham and Egan reports has led to significant advances, but which has not yet fulfilled all its potential. There is still much to be done before a customer-focused, integrated and cost-effective industry that delivers high quality and sustainable outcomes is the norm rather than the exception. Ministerial leadership can play an important part in helping the industry to continue to raise its game. To do this ministers must be given the time and the opportunity to deliver.