Clydesdale and Yorkshire Banks have reported a doubling of pre-tax cash earnings, despite continuing to face legacy issues such as payment protection insurance payouts.
Profits for the six months to the end of March 2014 came in at £89m, up from £44m for the same period last year.
Underlying profit was up by 6.7% to £144m.
Glasgow-based Clydesdale and the Yorkshire brand make up National Australia Bank's UK operations.
NAB has been restructuring its struggling British operations, shedding jobs and shrinking its commercial lending activities in a bid to build "a better bank".
In the latest half-year, it reduced charges to provide for bad and doubtful debts by almost 40% to £55m. It also cut operating expenses by 3.9% to £14m.
However, the banking group acknowledged that "the impact of legacy conduct related matters continued to negatively impact on performance", with additional provisions of £13m raised in the half.
Payment Protection Insurance (PPI) provision balances stood at £126m at 31 March 2014, down from £152m at the end of the previous quarter.
David Thorburn, chief executive of Clydesdale Bank and Yorkshire Bank, said the business had "continued to make good progress".
He added: "We're also making a significant investment in customer service improvements and there's a great deal of positive change underway.
"We're committed to building a better bank for our customers. I recognise there's a great deal more to do but I firmly believe we're on the right track."
In March, it was announced that Clydesdale and Yorkshire Banks would close 28 "unsustainable" branches and invest £45m in customer improvements under plans to reshape their retail banking operations.
The banking group expects to save £5m by the branch closures.
It is also spending more than £20m on improved mobile and internet banking services as part of the programme to "replace, renew, relocate and reinvest" across the retail branch network.Source: BBC News Scotland Business