The appointment will be effective for the 31 December 2018 year-end and is subject to shareholder approval at the next annual general meeting due to be held in May 2018.

KPMG will continue in the role until the audit of the group's consolidated accounts for the year ending 31 December 2017 has been completed.

In a statement, STB said: ‘The board would like to thank KPMG for their contribution and dedication over the years. We look forward to a constructive and professional relationship with Deloitte in the future.’

According to its 2016 annual report and accounts, the retail bank paid KPMG a total of £761,000 in fees for the year, compared to £528,000 in 2015.  The 2016 fees were £213,000 for audit and £548,000 for non audit services.

Founded in 1954, STB was admitted to AIM in November 2011 and in October 2016, listed on the main market of the London Stock Exchange. The non-audit services comprised acting as reporting accountants, non-statutory audit of historic financial information, interim profits verification, tax advisory services and assurance services in connection with the Funding for Lending Scheme.

The STB audit committee stated in the annual report: ‘At its meeting in September 2016 the committee assessed the objectivity and independence of KPMG as external auditor. The committee considered general procedures to safeguard independence and objectivity, independence and objectivity considerations relating to the provision of non-audit services and independence and objectivity considerations relating to other matters.

‘In particular, consideration was given to the fees payable to KPMG for their work as reporting accountants in relation to admission and other non-audit fees payable to KPMG.

‘The committee is satisfied that these non-audit services did not adversely impact the independence of KPMG’s audit services.’

Report by Pat Sweet