HEAVYWEIGHT management consultancy Boston Consulting Group (BCG) has been brought in to advise on restructuring at Clydesdale Bank, in a move likely to raise fears that this will be a major exercise which could involve significant job losses.

The Herald understands BCG is working with chief executive David Thorburn at Clydesdale's Glasgow headquarters as he investigates ways of boosting returns at the bank which has been hit by a doubling in running costs since the credit crunch.

Meanwhile, analysts at investment bank UBS said investors are pressing Clydesdale parent National Australia Bank to sell its UK unit and focus on expansion in fast-growing markets in Asia.

A sale could net NAB between £1.9 billion and £2.6bn, its research note said.

As reported in The Herald last Saturday, start-up bank NBNK remains interested in buying Clydesdale as a means of establishing a base in the UK retail banking market.

BCG describes itself as a "global management consulting firm and the world's leading adviser on business strategy".

It has been involved in high-profile work such as the restructuring of troubled American car makers General Motors and Chrysler, and has advised on controversial moves to streamline the US Securities and Exchange Commission.

The privately-owned group's alumni hold top roles in public and corporate life across the globe. Former staffers include Republican presidential challenger Mitt Romney, Andy Hornby, former chief executive of Halifax Bank of Scotland, and Mark Joiner, NAB's finance director.

It is known for techniques such as its growth-share matrix which allows companies to differentiate strong and underperforming businesses.

National Australia Bank has highlighted its determination to cut costs at Clydesdale and Mr Thorburn has already warned of job losses.

He signalled that its commercial property business, where he said "the economics are challenging" will come under particular scrutiny.

Clydesdale has seen bad debts rise due to the stalling economic recovery and another dip in the property market.

Further pressure has been heaped on the bank by a succession of credit rating cuts.

Clydesdale, which includes Yorkshire Bank, has more than 300 branches and 2.7 million customers. It has more than 4200 employees in Scotland and announced 279 job losses before Christmas.

The outcome of its review is expected to be announced in early May.

UBS analyst Jonathan Mott wrote in a research note this week that NAB's shareholders are keen to see the back of Clydesdale, which it bought in 1987.

"We believe investors have a strong preference for NAB to announce a sale of the UK even at a large discount to book value, given – the UK has no strategic value, is sub-scale, and is facing ongoing economic and regulatory pressures.

"In our view it would be in shareholders' interests to 'stop-loss' and return the residual capital to Australia."

NAB has repeatedly said it is committed to pursuing organic growth in the UK but would consider other opportunities.

Mr Mott said he believed Clydesdale has two options: go into run-off or divide into a good bank and a bad bank.

The latter option would likely see its business banking network in south east England closed and loans run down.

This would leave it focused on Scotland and northern England with repriced loans and deposits and aggressive cost cutting. "This now appears most likely," he said.

A Clydesdale spokesman said: "NAB has commenced a strategic review, and will work with UK management to appropriately reposition its business mix and structure for the changed economic environment and improve returns.

"We will inform the market of the outcomes of the review, which we expect to occur by the time of our interim result in May 2012."

A BGC spokeswoman said: "As a matter of policy, the Boston Consulting Group does not comment on its work with companies."