IF, so the idiom goes, it is impossible to be just a little bit pregnant – you either are or you are not – can an organisation be partly mutual?

This is a question customers in Co-operative Bank will be asking after the institution unveiled a restructuring plan that will see shares in the bank traded on the stock market, as they are with established names such as Royal Bank of Scotland or Barclays.

This is good news, according to Euan Sutherland, the Scot who has had a turbulent time since joining Co-operative Group as chief executive last month.

Shareholders can "share in the upside" of Co-operative Bank's recovery.

But it is less clear that it is beneficial for Co-operative members and mutualism more broadly, although alternative plans were few in number.

Just a few months ago, Co-operative Bank was pursuing a deal to buy 632 branches from Lloyds Banking Group. This would have had a transformative effect on the Scottish banking market where RBS and Lloyds are dominant, creating an institution with nearly 200 branches north of the Border.

It would have shown that alternative models to the stock-market listed bank were possible. This would have had particular resonance in Scotland, where the co-operative movement has strong roots.

While a stock market listing has many benefits, such as the ease of raising capital and efficient pricing, it comes with significant drawbacks.

It tends to the prioritisation of short-term financial targets above other considerations, whether ethical or longer-term business development.

Co-operative Bank remains "strongly mutual", Mr Sutherland insists. But it seems that yet another route to reforming the banking sector has been closed.