But this gratis greedfest has left a bitter taste in the mouth and now the leftovers of the mutual sector are fighting back. Some customers of converted building societies, such as the Halifax and Abbey National, complain they are being penalised by the need of their banks to satisfy greedy shareholders. Many have voted with their feet by pocketing their windfalls and promptly taking their business back to remaining mutuals like the Nationwide and Britannia.
Elsewhere, the head of the John Lewis Partnership has mounted a spirited defence of the department store group's mutual status in the face of workers baying for pounds 100,000 windfalls that demutualisation could bring. Could it be that the AA, which last week was sold to Centrica, will go down as the last great demutualisation?
The evidence is strong that, in spite of all the defections, the mutual sector is in rude health. That was the conclusion of Charles Leadbeater and Ian Christie, members of the left-wing think-tank Demos, who recently published a book called To Our Mutual Advantage. They estimated that organisations owned by their members had a combined annual turnover of pounds 25bn and employed 250,000 people. The sector encompasses activities as diverse as child care and Neighbourhood Watch, but it is in the arena of building societies where the arguments for and against mutuality have been propounded.
It is a debate where the pro-demutualisers have held sway. Since 1989, when Abbey National set the ball rolling, a series of building societies have surrendered their mutual status. Those 10 years have provided ample opportunity for the benefits of demutualisation to be identified, but the signs point the other way. Figures from the Building Societies Association suggest mutuals are increasing their share of mortgage lending.
David Holmes, a spokesman for the mutual Yorkshire building society, says: "We decided demutualisation would mean mortgage rates going up and savings rates going down because when you float you have to pay out pounds 35 in every pounds 100 in dividends."
Brian Davis, chief executive of the Nationwide building society, says: "We're picking up a lot of business because we can offer lower prices, but there's more to it than that. Our motivation is not to be money-grabbing. Unlike plcs, we don't get patted on the back by shareholders if we make more money."
It is not an argument which the convertors would accept but the mutuals are eager to ram it home. On Friday, the Nationwide threatened to sue Barclays unless it rescinded a plan to charge the customers of other banks pounds 1 for using Barclays cash machines. Nationwide was fighting this cause for its members, the mutual proclaimed, unlike Barclays which only cares about shareholders.
Just a publicity stunt, maybe, but the Nationwide's stance reflects the growing confidence among mutuals that they are winning the argument. This is bolstered by knowing mutuals are no longer sitting ducks. Like several other building societies, the Nationwide has created a charitable foundation so that would-be carpet-baggers would have to give their demutualisation windfalls to charity. Nationwide's status has been strengthened by the adoption of higher voting thresholds.
Mr Davis, who carries the baggage of the Nationwide's 150- year history, is conscious of the burden of posterity. Mutuals exist not just for the benefit of current members but also for future ones, so the moral justification for one generation cashing in at the ex-pense of the next is questionable.
"It makes you wonder if you can join an organisation by depositing pounds 100, then get it back plus pounds 1,000, when the fact is that it destroys that organisation and deprives your kids of it," he says. "I can see why people are tempted, but you shouldn't just destroy it for a one-off gain."
History is preying on the mind of Sir Stuart Hampson, who took over the top job at John Lewis from a member of the founding family. Sir Stuart's commitment to public service is evident in his defence of the group's unfashionable structure. "Being a partnership means that you offer something different in terms of employing your partners," he says. "They are not mercenaries, but citizens."
Despite last week's announcement of a 22 per cent profits slump, he believes that the company is well-served by worker ownership: "Customers see the involvement of our staff and feel there is a quality of trust and integrity, fairness and care."
His argument seems to be prevailing. Paul Fineman, who works for Peter Jones in London's Sloane Square, has tabled a resolution about John Lewis's structure at tomorrow's meeting of the company's central council, but the signs are the status quo will be endorsed. Not even the lure of pounds 100,000 windfalls for each of John Lewis's 40,000 staff would appear to be enough to persuade them.
It may be that the resurgence of the mutual is a dead cat bounce. Normal service may be resumed next year when members of the Bradford & Bingley decide its future. But there are signs that the remaining mutuals will be ready for the next onslaught.