Newly-listed UK bank Shawbrook Group has said its first-half profit nearly doubled, driven by an increase in its loan book.

The bank, which was founded in 2011 and went public this year, said it remained well-placed to respond to the changing regulatory environment.

That comes just a few weeks after Chancellor George Osborne announced an eight per cent surcharge on banks' profits effective January 2016.

Shawbrook's underlying pretax profit rose to £34.8 million for the first half ended June 30, from £17.9m a year earlier.

The bank's loan book grew 38 per cent to £2.72bn, from £1.97bn.

Shawbrook said net interest margin remained stable at 6.1 per cent in the first half of 2015, helped by continued reduction in the cost of funds.

The bank is aiming to maintain net interest margin at about six per cent in the medium term, according to the target set during the initial public offering.

The bank said its balance sheet was positioned to benefit from rising interest rates. However, the timing of the anticipated benefit was uncertain.

Shawbrook is one of several challenger banks to emerge since the financial crisis.

Former Royal Bank of Scotland chief executive and chairman Sir George Mathewson recently stepped down from his chairman role at Shawbrook having been with the business since it was founded in 2011. Sir George had stated he would not stay in the role once the flotation of the bank was completed.

He was replaced by Iain Cornish, previously of Yorkshire Building Society, earlier this month.