Aviva has appointed Maurice Tulloch as its new chief executive officer with immediate effect, the insurer said today. 

Company chairman Adrian Montague, who had temporarily stepped in as CEO following Mark Wilson's ouster last October, will revert to his role as non-executive chairman. 

Tulloch joined Aviva in 1992 and was heading Aviva's international insurance business with responsibility for Aviva's life insurance and general insurance operations in France, Canada, Ireland, Italy, Poland, Turkey and India. 

His promotion to the top job was a unanimous decision by the board on Sunday night, a spokesman said.

The long-awaited appointment comes as the British insurer faces major challenges to deliver more shareholder returns. 

Aviva's "composite" model under which it sells everything from life to car insurance has so far failed to deliver the same results as more focused rivals like Prudential and Legal and General. 

Tulloch was previously CEO of Aviva UK and Ireland General Insurance, one of the largest businesses in the Aviva group. 

He was appointed to the board in June 2017 and was part of the leadership team which helped Montague run the company while the executive search was underway. 

Another board member, Andy Briggs, who heads Aviva's UK insurance business, was also a frontrunner for the job. 

Tulloch is expected to sharpen Aviva's focus on the home market and some analysts say he may decide to put some overseas units under review, including its Asian business. 

Under Wilson's leadership, Aviva clinched one of the biggest insurance takeovers in a decade by buying Friends Life in 2015. 

But despite improving profitability, Wilson failed to turn Aviva share price performance around with the company's stock up 25% during his tenure compared to a 61% return for the insurance sector within the FTSE-100. 

Formed through the merger of Norwich Union and CGU in 2000, Aviva can trace its heritage back to the Hand in Hand insurance company which was established in 1696, 30 years after the Great Fire of London.