Sir Denys told the International Monetary Conference in London that some banks welcomed volatility in the markets because it 'generates excitement and the prospect of large, instant gains', but this usually ended in tears for bankers and clients - as it did in 1989.
He said only successful, youthful merchant bankers seemed to benefit from the turbulence, through what he called the 'excessive personal rewards which are so hard to justify by the normal standards of industrial remuneration'.
Sir Denys, a non-executive director of Barclays, said that when he became chairman of ICI in 1987, he was 'astonished by the never-ending flow of advice, mainly about novel financial instruments and sparkling acquisition prospects which it was suggested I dare not ignore'.
He said these were often kites that were being aggressively flown, but as the 1980s became more frenetic it also became increasingly difficult to find advisers who were reasonably objective.
He called for a balance between objectivity and peddling what he called the deal of the day.
Bankers should also work harder to understand their clients' businesses, he said, and take a long-term supportive stance through fair and foul weather - which he saw as the normal model in the Asia Pacific region, particularly Japan, and in Germany.
Sir Denys said: 'I believe firmly in long-term banking relationships, where trust, loyalty and an appreciation that each party has a need for profits can be built up bilaterally over a period.'Reuse content