All that is to change. Following Sir Richard's abrupt departure after a collapse in trading and a boardroom row, the company is desperately seeking a non-executive chairman to oversee the recovery with new chief executive Peter Salsbury. Whithead Mann, the headhunting firm, has been appointed. The search, it says, will be global.
But what sort of person would the City like? Do analysts and fund managers want a retailer or an established plc man from beyond the high street? Do they want a UK figurehead or someone from overseas? The City's views are vital as M&S needs to repair its reputation in the Square Mile.
M&S says it is looking for "a combination of talents and a track record of delivery in a major organisation". It wants the chairman "to work with the board to take the company into the future successfully".
The City sees the job as rather less conciliatory. "The ideal chairman would be well-respected, diplomatic and have the guts to sack a chief executive," one analyst says. Another suggests the man will be "a cross between Moses and Attila the Hun".
The reason a tough guy is needed, one analyst says, is because "M&S does not need a makeover, but a revolution". There are still some concerns that after spending all his working life at M&S, Mr Salsbury might find it hard to be sufficiently ruthless.
The core of the City view is this: the chairman must come from outside the company and introduce a number of new executives not weighed down by the historical baggage of the Baker Street culture.
The logical extension of this, confirmed by M&S's claim that it is "casting the net globally", is that the new chairman might come from overseas. As the general analysts' view holds that the post could only be filled by an English speaker, this points squarely to the US.
Others say appointing a chairman from overseas might prove difficult given that M&S's business is still dominated by UK sales, and an oversees appointment might jar with the company's peculiar culture.
A home-grown candidate seems likely, then, but there are pitfalls. A strong chairman should not be seen as a potential vote of no confidence in Mr Salsbury. Archie Norman, the Asda chairman, is favoured but might struggle on this score. His record at Asda and overall standing make him an obvious choice, but as one analyst put it: "It easy to imagine quite a bit of tension with Salsbury... It would be frustrating for him [Mr Norman] not to be in full control."
Other possibles from retail include Lord MacLaurin, the former Tesco chairman, and Lord Blyth, who retires from Boots next summer. Neither is a free agent yet, but they seem to fit the profile. Analysts say they are valid choices, but warn difficulties could arise if neither is ready to "go native" with M&S's culture.
But some fund-managers take the view that as the practical side of the turnaround is covered by the executive team, there is no compelling reason a non-executive chairman should come from retail. "It would no doubt be useful if there was some kind of consumer experience," said one, "but it is conceivable that M&S might benefit from a chairman with a marketing, banking or even accountancy background." Some say that Sir Dominic Cadbury, the chairman of Cadbury Schweppes, may be in the frame.
Another mentioned is Sir Peter Davis, head of Prudential, whose financial credentials give him the heavyweight status required. Sir William Purves, former HSBC chairman, comes up for similar reasons. Some even say Sir Nigel Rudd, the Williams and Pilkington chairman, might figure.
As one analyst sees it, however, more important than the choice of chairman is setting out his exact role as a hands-off player. "The chairman should leave the job of sorting M&S out to the executive directors, and get on with running the board. What M&S needs is a past master at explaining everything very clearly to all interested parties."
This view finds support with fund managers. "M&S is a very special case. It is such a household name, so much a part of British life, that the job of chairman would almost be right for a politician," one says. Someone like Sir Leon Brittan, potentially free from his EU post from September, could appeal, although he is a rank outsider.
Finding a candidate willing to take on the challenge will not be easy. As analysts say: "At the moment there is no particular upside in becoming chairman of M&S." Kick-starting a flagging image could take more than a knighthood and a smile.