Lord Myners will receive a token £1 salary for his work as chairman of the Co-operative Group's internal governance review, set up to scrutinise the ethical organisation's democratic systems and control structures in the wake of the Paul Flowers scandal.

Labour's former city minister Myners has been appointed to the group's board as a senior independent director and will help Co-op to clean up its sullied reputation.

Co-op's banking arm has been the centre of the group's crisis. Its former chairman Paul Flowers, a Methodist minister, is on police bail amid a drugs scandal. The ethical lender also had to be partly bailed out by hedge funds because of a £1.5bn hole on its balance sheet, to the dismay of Co-op members.

"We have made it clear that we need to modernise and to embed the very best standards of corporate governance - while also ensuring that the voices of all our members and customers resonate through the business," said Ursula Lidbetter, chairwoman of The Co-operative Group.

"Paul [Lord Myners] is ideally placed to oversee that work given his extensive experience across business and public life."

The group pledged to review its "democratic structure" and stressed the need to "modernise" itself after the balance sheet hole was exposed.

Its internal review comes on top of two other inquires, one commissioned by the Treasury and another is being conducted by accountancy watchdog the Financial Reporting Council (FRC).

Police arrested former chairman Flowers, who was allegedly found to be embroiled in crack cocaine, crystal meth and ketamine-fuelled sex orgies, as part of an investigation into the supply of illegal drugs.

Co-op Bank is one of UK's smallest lenders with 6.5 million customers and a 1.5% share of the current account market.