A senior regulatory figure in charge of banking supervision at the Central Bank is leaving his position to return to the UK.

Jonathan McMahon, the director of credit institutions at the Central Bank, is stepping down from the role at the end of April to pursue other opportunities after more than two years in the job.

The Central Bank is changing its internal structures on his departure, combining the banking and insurance supervisory roles. Fiona Muldoon, director of insurance supervision, will assume Mr McMahon's responsibility for supervising the banks immediately.

Mr McMahon oversaw the stress tests of the banks last year and worked closely with the troika of the European Central Bank, the EU Commission and the International Monetary Fund on plans to resolve the banking crisis.

He also worked on the deleveraging plan for the banks, the reform of the regulatory system and the introduction of the new Central Bank Act, and on the enhanced supervision of the credit union sector.

He will continue to chair a committee reporting to the Financial Stability Board on the effect of the deleveraging on the Irish banks until his departure.

Originally from Sheffield in England, Mr McMahon worked at accountancy firm Deloitte, the UK regulator, Financial Services Authority and consultancy firm Promontory Financial Group prior to joining the Central Bank.

He joined the Central Bank shortly before the first round of stress tests in March 2010 and reported to Central Bank deputy governor Matthew Elderfield in his role.

Fiona Muldoon is to assume responsibility for the supervision of all financial institutions. following Mr McMahon's departure.

Ms Muldoon has been working for the Central Bank since last August in the newly-created role of director of insurance supervision and has 25 years' experience in the financial services industry.