Mr Booker, who has held a variety of senior roles at HSBC in a career of more than 30 years, warned he would be able to provide no “quick fixes” to improve Co-op Bank’s fortunes.
Mr Booker’s appointment, which is subject to formal regulatory approvals, comes after Moody’s Investor Services downgraded the credit rating of Co-operative Banking Group.
The ratings agency warned the bank may need “additional help” to raise new funds, raising the spectre of a fresh taxpayer bailout in the banking sector.
The downgrade was followed by Barry Tootell, chief executive, stepping down from his role and the board.
Mr Booker will take up his new roles at The Co-operative Group on 10 June.
Euan Sutherland, group chief executive of The Co-operative Group, said with his strong background across the banking sector, Mr Booker was the ideal person to lead the bank “at this important time in its history.”
He said: “He clearly brings the strategic and operational skills that we need to help take the Bank to the next stage of its development.
“The board and I are confident that Niall will add tremendous value, helping us work through the complex issues that we currently face as we work to re-position our bank. The Co-operative Bank has a strong future.”
Mr Booker agreed that this was a “strategically important” time for both the bank and the Co-op Group.
He said: “Along with the rest of the Co-operative team I will be focused on the actions to strengthen our balance sheet and satisfactorily resolve our underlying issues, while at the same time continuing to serve our existing customers and build on The Co-operative Bank’s exceptional brand strength. This will ensure that we are well placed to deliver a sustainable improvement in our banking business.
“There are no quick fixes here, but with the support of The Co-operative Group, our staff and our loyal customer base, I am confident we will be able to stabilise and develop the franchise.”