John McFarlane, currently chairman designate, will become interim executive deputy chairman and then executive chairman from 1 July.

Once a new chief executive has been found, Mr McFarlane will return to his non-executive chairman role.

Mr Moss said his decision was in the best interest of the company.

Lord Sharman, chairman of Aviva, said: “We should acknowledge the progress that has been achieved under Andrew Moss’s leadership.

“Through the global financial crisis he led the consolidation of our international presence and integration of 40 brands into the very powerful single Aviva brand.”

Mr McFarlane said: “Aviva is a leading company in the insurance sector and I’m excited to play a pivotal role in its transformation and future. I feel I can make a real difference.

“My first priorities are to regain the respect of our shareholders by eliminating the discount in our share price and to find internally or externally the very best leader to be our future chief executive.”

Aviva hit the headlines last week after losing a vote on executive pay at its latest annual general meeting.

Shareholders had previously voiced their concerns about pay after the publication of a remuneration report by the firm in March.

A further announcement will be made on the financial terms of Mr Moss’ departure.