The Skipton building society is gathering a war chest of up to £400m to fund rescues of some of its struggling rivals.

Britain’s sixth-largest building society, which has a £14bn loan book and 700,000 members, is considering a sale of at least three of its non-core businesses to raise cash.

The society’s credit-check agency Callcredit, its estate-agent chain Connells and mortgage-servicing business HML are all being groomed for disposal.

The move comes amid the Financial Services Authority’s programme of stress-testing for Britain’s biggest building societies, which is expected to lead to several of them being forced to find a merger partner.

Sunday Times