Businesses will struggle to recruit non-executive directors, with individuals reluctant to take up positions because of the risk and responsibilities involved, according to accountants Deloitte.
A report into board structure found that non-executive directors' fees have increased by ten per cent, a sharp rise compared with 5.8 per cent last year.
The median fees for non-executive directors now range from £32,500 in the smallest FTSE companies to £66,500 in the largest.
Andy Hodge, head of Deloitte's employer solutions practice in the Midlands, said: "Boards have undergone significant changes over the past year which has increased the responsibilities and time commitment of non-executive directors.
"The Combined Code has also put pressure on individuals to hold fewer nonexecutive positions and, with the requirement that 50 per cent of the board be made up of independent non-executive directors, the demand for high-quality individuals is increasing. All of this has impacted on fee levels."
FTSE 350 companies do not seem to be widening the search for suitable candidates. The majority of appointments are still likely to be from other large UK public companies.
There has been a very small increase in the number of female members on boards of FTSE companies - nine per cent of FTSE 350 nonexecutives, compared to eight per cent last year.
Currently, 16 per cent of FTSE 100 and 39 per cent of FTSE 250 companies have boards which comprise of less than 50 per cent independent directors. These companies would need to appoint an additional 145 directors in order to be fully compliant.
A high proportion of companies have now developed a more transparent fee policy, which includes a basic fee level and additional compensation for membership of a board committee.
Deloitte believes it may be harder to recruit nonexecutive directors in the year ahead as individuals are increasingly being put off by the risk, responsibilities and time commitment involved.