Allen & Overy (A&O) has made a series of internal promotions following the departure of finance director Ian Dinwiddie.

The magic circle firm has promoted IT director Jason Haines to take over the finance director role. Haines will also remain as IT director but will be supported by deputy IT director Gareth Ash, who is also the firm's chief information officer.

Dinwiddie left the City giant last month to become president of Thomson Reuters-owned legal consultancy Hildebrandt Baker Robbins, after 20 years as finance director at A&O.

Haines, who, like Dinwiddie, is a chartered accountant, has headed up A&O's IT function for three years since joining the firm in 2007 from PricewaterhouseCoopers, where he was global chief technology officer.

Commenting on the promotion, Haines said: "It is really exciting and a great new challenge. I previously worked in finance for a long time so it feels very good to be back in my old area. Being a finance director is a very challenging but interesting role."

The appointment also means that Haines has replaced Dinwiddie as a co-opted member on A&O's global board, which underwent its four-yearly revamp earlier this year, with three partners replaced.

The news comes after A&O's annual financial report showed remuneration for the firm's main management group – which includes the firm's senior and managing partner, global practice group heads and support directors – increased 43% between 2008-09 and 2009-10. The group received £14.2bn in total, including directors' bonuses.