Highly experienced and consequently highly rewarded, interim managers are playing an ever-increasing part in the development and maintenance of systems in organisations as diverse as charities, government bodies and hedge funds.

More closely involved in the aims and ambitions of their clients than the average consultant and far more senior than the average ‘temp’, they are able to pick and choose amongst lucrative and challenging assignments and to earn as much as £2,500 per day. But who exactly are they and why is their use currently proving so popular across the IT arena?

Interim managers tend to be senior IT managers or directors who have stepped off the corporate treadmill to become guns for hire, moving from assignment to assignment.

Operating through their own personal services companies they provide a short-term injection of heavyweight knowledge and experience focused on a specific set of packages, a particular industry or a defined corporate project such as the establishment of a shared services centre. In so doing, they allow organisations to throw a huge amount of skills and experience at a problem for a relatively short amount of time without the fear of a long-term burden on the payroll.

For the harassed director or HR department , they can supply the ideal way of plugging a senior staffing gap, perhaps caused by an unexpected resignation or maternity or sickness leave.

However these are not necessarily the roles when the interim can provide the very best return on what can be a fairly hefty financial investment. Instead their real value often lies in their ability to successfully manage the process of change and ensuring that projects are delivered on time and to budget. And the message about how to extract this maximum value seems to be getting through to potential buyers, according to the Interim Management Association, the industry’s own trade body, the market for interims will exceed £1bn next year.

One of the key reasons for choosing to hire an interim manager over a conventional contractor or consultant is the fact that they don’t just provide strong technical expertise but also sharp political and inter-personal skills.

Although many interims may have set out on their new career to get away from the everyday turmoil of internal politics, they still need to grasp the nature of the power structure within any client organisation and then exploit it. This is essential because interims must be able to gain trust and respect quickly and then motivate and direct those around them if they are going to get the job done effectively.

Interim managers also need to be natural trainers because their role is not just about the deployment of knowledge, it’s also about ensuring that it remains within the organisation after they leave. It’s consequently possible to define the most effective interims in the market by how quickly they put themselves out of a job and how well their team is operates in the weeks and moths following their departure.

Given their apparent value for money and the speed with which they can be deployed and become effective, it’s perhaps not hard to see why interims have become such an accepted part of the IT scene.

But why does a successful senior manager or director decide to leave a comfortable corporate job for the uncertainty of self-employment?

One of the major drivers is certainly the lure of substantial earnings. A survey of interims carried out by my own firm, Praxis, in January found the majority expecting to earn at least £100,000 in 2007. Another is the prospect of more control over work-life balance, many successful interims are able to take substantial breaks between assignments to focus on family or hobbies in a way that would be impossible on the corporate career ladder.

However, despite the ostensible attractions of working this way, interim management is certainly not right for every IT executive as some have found out too late. Self-employment means that you are only as good as your last assignment and it also means that if you are not out there selling yourself into your next project you simply don’t get paid. Remember that any freelancer must have a high degree of self-confidence and self-contentment if they are to succeed. The sort of person who defines their worth by their title, the number of staff under their control or how often they play golf with the MD is highly unlikely to thrive as an interim manager.

Claire Hain specialises in work in the IT sector at interim management recruitment specialists, Praxis