Portman has scored another point in the war against carpetbaggers by forcing new customers to donate any windfalls to charity.
From January 4 all new customers will be urged to donate any demutualisation windfalls to the Charities Aid Foundation, while existing members will be unaffected.
Carpetbaggers.com, the website devoted to demutualsing the remaining building societies, is arguing societies like Chelsea who don't have a charitable clause are not dedicated to mutuality.
But Chelsea Building Society is claiming the notion is “bizarre and lacking in sense.”
A Portman spokesperson says: “We've done this with reluctance, but we want to deter high volume speculative investment.”