The number of company directorships that any individual can hold is expected to be restricted to a maximum of 25, under new legislation due to be introduced shortly.

However, this figure is not expected to include directorships of companies within the same group, so the number of directorships an individual could hold could be much higher than 25 in practice.

No practical guidance is currently given on how many directorships any one director should hold. But it is hard to see how any one director could give a good service to more than about 10 to 15 companies, especially if some of the companies were large and publicly quoted.

For aspiring directors there are a number of important considerations. They can be personally liable to creditors if the company fails and is found to have been trading recklessly. Therefore, directors must ensure that the company is well run and has proper accounting and control systems in place before accepting appointments.

In addition, they should ensure that there will be no conflicts of interest between their new directorship and any other directorships they already hold.

Such conflicts can arise, for example, where the companies compete against each other in consumer markets or where they are competitors for building or other service work.

And nowadays in an increasingly litigious society company directors may be well advised to insure themselves against possible personal liability to creditors.

The Cadbury Committee on Corporate Governance recommended that to ensure public company boards can be independent of their own executive directors an adequate number of suitably qualified non-executive directors should be appointed. While cynics often see appointments of non-executive directors as rewards for previous services, or, the status effect of bringing big names on to the board, the usual reason behind these appointments is to bring in specific experience or expertise to assist in formulating strategy.

Almost anyone can become a director. Legislation and company constitutions are specific about who cannot become a director but are generally silent about who can. Certain classes of people are specifically prohibited from becoming company directors - persons declared bankrupt, persons of unsound mind, persons convicted of an indictable offence though generally offences under the Road Traffic Act are excluded.

In addition, people who have been directors of companies and have acted fraudulently and/or where the company has become insolvent can be barred by the courts from becoming a director or restricted in the type of company they can serve as a director. A list of the people proscribed from holding directorships is held at the office of the Registrar of Companies.

In 1912, the Equitable Fire Insurance case established that the primary responsibility of a company director was to act at all times in the best interests of the company.

In addition, company directors have a fiduciary responsibility to safeguard the assets of the company, to ensure that proper records and books of account are kept and that an appropriate system of internal financial control is in place.

But as the secretary of the Irish branch of the Institute of Directors, Mr Ralph McDarby, explained, company directors are not required to devote all their time to their duties as a director, but they are required to bring whatever skills they have to bear on the task.

The rule is that company directors are appointed by the shareholders. But in practice new directors are normally appointed by the board acting together and in its entirety, possibly on the recommendation of an appointment committee formed out of its members.

The new appointment then lasts until the next annual general meeting when shareholders must vote on it.

Directors usually hold a directorship for three years when they retire by rotation and shareholders must vote on their reappointment. For an appointment to be valid the appointee must consent to act as a director. How do the existing directors find a new director?

In most cases one or more of the existing directors may have someone in mind. But in a situation where the board is looking for a new member, the Boardroom Centre has a panel of skilled people willing to act as directors. Sponsored by the Institute of Directors and a number of big companies, the centre matches the skills of the panel members with the needs of the company looking for a new director.

The Institute of Directors regularly holds seminars to update directors on their duties and responsibilities and on best practice on corporate governance, Mr McDarby said.