A report into the near-collapse of UK life assurer Equitable Life has absolved government regulators of negligence, heaped blame on the firm's management but offered no compensation for policyholders.

The world's oldest life assurer almost collapsed in 2000 after the House of Lords, ordered it to honour guaranteed policies sold in the high-interest years of the 1970s and 1980s - a decision that cost it more than £1.5 billion and left thousands of policyholders out of pocket.

The 818-page report produced by Scottish judge George Penrose, which was two-and-a-half years in the making, criticised Equitable Life management for the crisis and said regulatory failings were "secondary factors". Lord Penrose found that a culture of "manipulation and concealment" among Equitable's senior management ultimately led to the financial weakening of the company.

Equitable Life had between 20,000 and 25,000 policyholders in Ireland. Last year the Tánaiste, Ms Harney, referred complaints from a number of these policyholders to IFSRA, the financial regulator. These related to allegations of mis-selling of policies

Seven action groups, representing around one million former and current Equitable policyholders, have called for £3 billion compensation from the government.

Treasury minister Ruth Kelly told parliament: "Lord Penrose makes no recommendation for the payment of compensation. His central finding is that "principally, the society was the author of its own misfortunes."

Lord Penrose's report said: "As for the regulatory system, I do believe that it has failed policyholders in this case." He made no allegation of maladministration or negligence against the regulator. The government has asked official fraud investigators to look into issues raised in the Penrose report.