The Equitable was once the UK's biggest private pension companies
A group representing people who lost money in Equitable Life is taking legal action against the government over its failure to offer full compensation.
The Equitable Members Action Group says the Treasury failed to act on recommendations for payouts from the Parliamentary ombudsman.
Thousands of people lost savings after the firm's near-collapse in 2000.
The Treasury, which is planning limited discretionary payments, says it has to be fair to policyholders and taxpayers.
Equitable Life, one of the UK's largest private pension providers, came close to collapse nine years ago after being ordered by the High Court to fulfil financial promises which it could not afford.
The subsequent saga saw more than a million policyholders suffer large cuts to the value of either their prospective or current pensions as the society struggled to stay solvent.
The Parliamentary Ombudsman, Ann Abraham, investigated the events leading up to the society's troubles and last year ruled that various government departments had been guilty of maladministration.
EQUITABLE: KEY EVENTS
January 1999: Equitable tries to abandon a guaranteed payment it can no longer afford
July 2000: The House of Lords says Equitable must honour its original commitments, forcing the company to put itself up for sale
December 2000: Equitable Life closes to new business after failing to find a buyer
March 2004: Lord Penrose's report says the society was the "author of its own misfortune"
July 2008: The Parliamentary Ombudsman says regulators failed to protect policyholders and calls for a compensation fund
She also called for the establishment of a compensation scheme for more than a million policyholders.
However, the government continues to deny some of her findings, and is going only part of the way to carrying out her recommendation for compensation.
A former Appeal Court judge, Sir John Chadwick, has been asked by ministers to design a scheme that will give voluntary payments to the "hardest hit" of Equitable's investors.
Paul Braithwaite, general secretary of the Equitable Members Action Group (EMAG), said: "The government's continued intransigence has forced us to take legal action.
"The proposed hardship scheme is totally inadequate, will take years to implement and looks like leaving 90% of victims out in the cold."
EMAG's lawyers say they have found flaws in the government's response to the ombudsman's Equitable Life report.
They claim the main legal challenge will be over what they say are the "lack of cogent reasons" the Treasury has given for its refusal to accept some of the ombudsman's findings.
The group is also challenging the narrow remit given to Sir John.
Stephen Grosz, head of public law at Bindmans, said: "We are asking the court to quash the response, forcing ministers to think again."
A Treasury spokesman said: "The government carefully considered the ombudsman's report and has agreed to set up a payment scheme that is practical and fair to both policyholders and taxpayers, and which can pay out as swiftly as possible.
"We have asked former Lord Justice of the Court of Appeal, the Rt Hon Sir John Chadwick, to advise on the fairest way to proceed."
EMAG wants the High Court to set an early date for the hearing, as it says that each day there are about 15 deaths among the people who lost money because of the problems at Equitable.