Former Serious Fraud Office (SFO) director Sir David Green has joined Slaughter and May, following months of speculation over his move to private practice.

Green, who stepped down from the SFO in April this year, had led the government department since 2012 and had been linked with a number of major law firms both in the run-up to his departure and since. Legal Week revealed he was in discussions with Slaughters in May.

Green, who was knighted earlier this year, will join the magic circle firm as senior consultant on 22 October, six months after his departure from the SFO.

Green said: "I am delighted to be joining a firm which has such a deep understanding of the interests and needs of companies and individuals facing criminal investigations across the world. Slaughter and May is a natural fit for me and I look forward to being a part of the firm's global investigations practice, which rightly enjoys a pre-eminent reputation."

Green's tenure at the SFO encompassed a number of investigations into Slaughters clients, including Rolls-Royce and Olympus, while the magic circle firm is also advising Ultra Electronics and British American Tobacco (BAT) on ongoing probes, which had raised concerns over the implications of Green joining the firm.

However, several City white-collar partners played down concerns over possible conflicts issues to Legal Week earlier this year and, in announcing his move, Slaughters confirmed that he will not work on matters in which he was involved while at the SFO.

The hire of Green comes after Slaughters also sealed the hire of investigations and litigation lawyer Wynne Mok from the Hong Kong Securities and Futures Commission, the firm's third-ever lateral recruit.

Slaughters senior partner Steve Cooke commented: "David's appointment is another step in the ongoing success of the key contentious side of our practice, which is of ever-increasing importance to clients around the globe. We recently promoted two dispute resolution partners in London in addition to Wynne's arrival in Hong Kong – collectively these appointments will build on our outstanding reputation for managing high-profile disputes and investigations on a global scale."

During his tenure as SFO director, Green championed the use of deferred prosecution agreements (DPA), entering into a DPA with Rolls-Royce following a four-year investigation into false accounting and failure to prevent bribery. The DPA saw the company agree to pay out £497.25m last January – a fine that remains the largest-ever settlement with a company in the UK for criminal conduct.

Slaughters advised Rolls-Royce during that case, with the magic circle firm regularly acting on behalf of clients involved in SFO investigations. It is currently advising longstanding client Ultra Electronics in relation to suspected corruption charges.

The firm was brought in to advise the SFO itself in 2013, when Robert and Vincent Tchenguiz took legal action over its aborted investigation into the brothers for suspected impropriety in relation to the 2008 failure of Icelandic bank Kaupthing, a dispute that was settled in the summer of 2014.

Other high-profile matters during Green's time at the SFO include Tesco's DPA in April last year, which saw the retailer agree to pay out £129m to avoid prosecution after overstating its profits in 2014.

In an interview with Legal Week in March this year, Green discussed changing the perception of the organisation to "bring it to the top of its game as a crime-fighting institution".