The future of the Clydesdale bank has been thrown into doubt again after the new boss of parent group National Australia Bank (NAB) launched a review that could look at selling its British banks.

Cameron Clyne, who took over from Scot John Stewart as chief executive of NAB on January 1, has said his main priority would be to deliver shareholder return.

The British banks — Clydesdale and Yorkshire — are at risk because institutional investors in Australia are said to be unhappy at what they see as lower returns from British operations.

The NAB refused to comment on the UK banks’ future.

NAB’s shares have underperformed in recent years as Stewart sought to restore its reputation following a foreign exchange scandal.

Clyne, 40, has already shown his determination to stamp his authority by taking over the running of NAB’s profit-driving Australian businesses in addition to the group role.

Clyne, who previously ran the bank’s New Zealand operations, has admitted there were some “question marks” over the strategy of the business, without going into detail.

In its full year results revealed at the end of October, profit at Clydesdale was up 11.9% to £519m.

Any move to sell Clydesdale would be unwelcome in Scotland after the loss of HBOS to Lloyds and RBS’ problems, which saw the government take a large stake in the bank.

But a senior UK banking source said he would be surprised if the review led to a sale.

“The UK businesses are well run, lean and profitable and Clyne knows them well,” he said. “In addition, the currency fluctuations are in the UK’s favour. You also have to ask who could afford to buy it just now?”

NAB sold its Northern Irish banks four years ago for £1 billion. At the time, Clydesdale faced a potential sale as it was underperforming, but instead Stewart chose to invest in a radical restructuring which saw a large number of branches close and a focus on new financial centres.

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