Debbie Crosbie appointed acting CEO at Yorkshire and Clydesdale banks

The married mother-of-one will lead the banks until the arrival within the next few months of David Duffy, the incoming CEO.

He is joining from Allied Irish Banks, having led a turnaround of the state-owned lenders, and will be tasked with preparing Yorkshire and Clydesdale for sale, probably via an initial public offering.

National Australia Bank is keen to exit the UK banking market after years of underperformance.

NAB is understood to have appointed Morgan Stanley and Macquarrie to advise on its options.

Ms Crosbie, who is from Glasgow, was appointed an executive director at Yorkshire and Clydesdale in May 2014 and leads the banks’ work on customer trust and confidence.

The area was created in an effort to win back the trust of customers following the mis-selling of payment protection insurance and interest rate hedging products that have cost the lenders more than £1.2bn in provisions.

Ms Crosbie’s role expanded in October when she took on additional responsibilities for operations and IT after the departure of chief operating officer John Hooper.

The 44-year-old was promoted to chief operating officer last month, announced the same day as the appointment of Mr Duffy as CEO.

Mr Duffy is replacing David Thorburn, who is standing down after nearly four years in the role. He was formerly deputy to previous CEO Lynne Peacock.

In a first quarter trading update, NAB said its UK banking business is in “good shape and is well positioned for sustainable future growth”.

It reported “encouraging growth” in key retail products in a competitive pricing environment where industry-wide margins remain under pressure.

NAB said UK residential mortgage lending balances broke through £19bn for the first time with growth again ahead of the industry average.

Mr Thorburn said: “Good progress continued to be made in moving the business forward in the first quarter of the financial year.

“Further significant steps were also taken in the quarter to increase our support for customers, delivering a wide range of product and service improvements from current accounts and mortgages through to mobile and internet banking.

“More improvements are in train as part of our clear aim to build a better bank for customers.”

His last day with the business will be February 28. Ms Crosbie will become acting CEO from February 16.

Mr Thorburn led the business through a deep restructuring exercise, involving the axing of 1,400 jobs and the retrenchment to the northern and Scottish heartlands.

The UK business also quarantined £5.6bn worth of troublesome commercial real estate loans. This portfolio has now been reduced to around £800m, NAB said.

Speaking to The Yorkshire Post, Mr Thorburn said: “I feel I am leaving the business in good shape.”