Age Concern England's loss-making membership organisation Heyday is to close after a highly critical report by the Charity Commission.
In a regulatory case report published on Monday, the commission accused ACE trustees of falling short of expected standards and said its 34-strong board was too large.
"The trustees are unable to demonstrate that they exercised a sufficient oversight and critical challenge in making relevant decisions against a clear and robust risk framework," the report says.
The commission questioned whether there was enough evidence of need to justify setting up Heyday, a £26-a-year scheme aimed at those nearing retirement that offers benefits such as access to products and services. It also raised doubts as to whether all Heyday activities were clearly charitable.
Andrew Hind, chief executive of the commission, said it expected trustees to be accountable and transparent and make decisions in an "informed manner".
The commission recommended that the trustees instigate an independent external review of how Heyday was managed, including a full financial review.
A joint statement by ACE and the new charity said it had commissioned Sir Christopher Kelly, former chair of the NSPCC, to publish a report on what could be learned from Heyday.
Tom Wright, chief executive of the charity being formed by the merger of ACE and Help the Aged, said it was developing "a new and exciting approach to how it engages with older people" to replace Heyday.
He added: "We are working closely with ACE to ensure the new charity is listening to what older people tell us."
Gordon Lishman, director general of ACE, who retires next month, said: "I accept my full share of responsibility for the failure of Heyday to meet its objectives."
He said staff and trustees were committed to learning the lessons from its failure. There have been no resignations at the charity.
Launched in May 2006, Heyday received £22m from Age Concern and Age Concern Enterprises, the charity's business arm, between 2004 and 2008 and accrued membership income of £700,000. The charity put in £5m of reserves.
It had hoped to recruit three million members in five years and 300,000 by March 2007, but by then only 44,000 had joined.