Sky News has learnt that Debbie White is the leading candidate to replace Allan Leighton at the helm of Britain's biggest mutual.

If confirmed, Ms White would become only the second female chair in the Co-op's history, which can be traced back nearly 180 years.

Her appointment would place her at the top of an organisation with more than five million members, making it one of the world's largest consumer co-operatives.

Its operations include the UK's fifth-largest food retail business, while it is also a major player in the British funeralcare sector and retains a presence in the legal services and insurance markets.

Ms White, whose previous roles include running the UK arm of Sodexo, the contract caterer, recently had a stint in a senior human resources role at BT Group.

During the pandemic, she played an important part in establishing the network of testing centres that formed part of the government's response to the unfolding crisis.

She now sits on various public company boards, including that of Howden Joinery Group and Spire Healthcare.

Ms White's appointment at the Co-op Group could be announced as early as Thursday morning.

She would replace Mr Leighton, one of Britain's best-known businessmen, who has held the role since 2015.

Mr Leighton was parachuted into the role in the aftermath of the biggest crisis in the mutual's history, with its future cast into doubt two years earlier by funding and governance challenges.

The Co-op was left reeling in 2013 when it emerged that its banking arm was facing a £1.5bn black hole as it tried to acquire more than 630 branches from Lloyds Banking Group.

The bank's chairman, Paul Flowers, was subsequently exposed by a tabloid newspaper as a serial drug-user, plunging the Co-op name deeper into crisis even as it surrendered control of its high street lending arm to American hedge funds.

Separate independent inquiries led by Lord Myners, the former City minister, and Sir Christopher Kelly, a former civil servant, concluded that there was a need for an urgent overhaul of the Co-op's governance, board structure and array of commercial activities.

There was further turmoil at the top of the mutual in 2014 when Euan Sutherland - now chief executive of Saga - quit as the group's chief executive after details of his pay package were leaked to the media.

Mr Sutherland was replaced by Richard Pennycook, a former director of Wm Morrison, the supermarket chain.

Since that time, Co-op members have voted to approve reforms including reducing the number of lay directors on its board and the appointment of a majority of independent directors.

Under Mr Leighton, the group has transformed its performance and governance.

It has raised roughly £1bn from the sale of its petrol retail chain, pharmacies and the bulk of its insurance operations.

The Co-op declined to comment on Wednesday.