John A. Byrne, a senior writer at Business Week and author of the hard-hitting Heinz cover story, says that if Dr Tony O'Reilly does not change the board then the pension funds are likely to become more aggressive.

"The issue here," he told The Irish Times, "is that in the past 18 years, Dr O'Reilly has run the board as he saw fit - the way boards were run in the 50s and 60s, not in the 90s".

He believes there is considerable pressure on Dr O'Reilly to name Mr William Johnson as CEO otherwise he risks losing him, "and that would be disastrous". The cereal company, Quaker Oats, for example, is looking for a new CEO and "Johnson is way up there in that search," says Mr Byrne.

In his article he compared Heinz's governance to Campbell Soup Company which, until 1990, was a family run business. It then became revitalised when David W. Johnson was hired as chairman from Gerber Products Company.

Ted Smyth of Heinz contends that the two companies only compete in the soup market and therefore it was not a fair comparison. "Over 20 years our annualised returns to shareholders were 21.8 per cent and 20.6 per cent for Campbell," he said. Since 1992, however, Campbell's returns have improved significantly. But Mr Byrne argues that his story was about governance, not necessarily performance. He pointed out that in 1989 Heinz led all the food companies in the US with a value of $6.3 billion, 60 per cent more than Campbell. Today, Campbell leads all food companies with $21 billion in value and Heinz has fallen to third place with a value of $16 billion.