"It would be a crying shame if we lost the very valuable pool of talent willing to take on the role of non-exec director, " said PricewaterhouseCoopers (PwC) partner Bob Semple. "They bring a level of balance to the board. If you have only executive director, there's a danger of not seeing the wood through the trees."

PwC and the Institute of Directors recenlty launched a guide for non-excecutive directors explaining their responsibilities under updated Irish law.

Non-executive directors are essential to offer caution and constructive criticism, said Semple.

The guide offers advice both to directors and companies, urging clarity in letters of appointment, holding an induction session for new directors and charges directors with honestly outlining risks to the business.

Semple added that US legislation like Sarbanes-Oxley is so onerous it's the subject of black humour in boardrooms.

Under the law, a CEO or CFO could face up to 20 years in prison if things go Enron, whereas manslaughter has a maximum sentence of 16 years in most US states.

"So you'd be better off killing the CFO. You'd get four less years, " said Semple, who stressed that this advice was not in the PwC guide.