Though now best known as a newspaper magnate because of his chairmanship of Express Newspapers, Lord Stevens' greatest claim to fame in the City has been as a merchant banker and fund manager.
But when he bowed out as chief executive of Invesco MIM last summer, Lord Stevens' City power base began to shrink dramatically, culminating in April in a decision to stand down early as chairman, instead of waiting for the planned date this month.
Last summer, colleagues said he was resigning as chief executive because of the poor performance of Drayton Consolidated Trust, managed by Invesco, the need to split the roles of chairman and chief executive and the bad publicity surrounding the group's role as a manager of Maxwell pension funds.
That explanation will now be seen against the background of the harsh criticisms by Imro of Invesco MIM's mishandling of assets under his stewardship.
The fact that his old firm has now paid the biggest fine ever levied by Imro, one of the key City regulators, is likely to come as a bitter blow.
It is hard to underestimate the importance of Lord Stevens' now fading City power base to the development of his outside career.
His role at the fund management group MIM, formerly Montagu Investment Management, was the springboard in 1981 to the chair at United Newspapers, the stable of provincial newspapers.
MIM was a substantial shareholder with a long connection with United and the then David Stevens became the group's representative on the board in 1974. Seven years later, by which time he was MIM chairman, he was chosen for the top United job when Lord Barnetson died.
In 1985, having built up United, Lord Stevens used it to bid for the Express newspaper group, using a 15 per cent stake bought from Robert Maxwell as the platform.
His career was closely linked at several key moments with Maxwell. They came to be known as the Captain and the Corporal, a reference to Lord Stevens' Napoleonic ambitions rather than his rank.
In 1986 MIM - still run by Lord Stevens - teamed up with Maxwell as white knights to save Britannia Arrow from a bid by the merchant bank Guinness Peat. Britannia was an investment management group rebuilt from the ashes of Slater Walker Securities.
The knights soon turned into dragons.
In what amounted to a reverse takeover, MIM was bought by Britannia, with Lord Stevens ending up running the lot. The company evolved through takeovers and name changes to become Invesco MIM.
The Captain and the Corporal were involved in a bid again when United Newspapers took over Extel, the financial information service. Maxwell sold a crucial stake, which paved the way for the takeover, to Lord Stevens in his United capacity. Once again, Lord Stevens' City and media interests coincided.
But he has always rebutted accusations that he has used investment funds under his management for his own ends by pointing to the rewards he has brought to shareholders.