When David Green stands down as Director of the Serious Fraud Office (SFO) in April, after six years, it will bring to an end a period that has seen major developments for the organisation. And yet many questions still remain about its effectiveness and its future role.

Issues such as Brexit, SFO funding and staffing, deferred prosecution agreements (DPA's) and its work with international counterparts are still to be fully resolved. There is little doubt that the SFO has taken significant strides under Green's stewardship. But for some observers, the SFO's precise direction seems unclear.

NECC

The issue of the SFO's direction is particularly notable when the National Economic Crime Centre (NECC) is considered. This time last year, the Prime Minister was drawing up plans to include the dissolution of the SFO in the Conservative election manifesto. Within a matter of months, this goal was quietly shelved amid mildly encouraging noises from government about the effectiveness of the SFO. This, however, did not signal a total backing of the SFO.

The government's announcement of the creation of the NECC, which will have the power to direct the SFO to carry out investigations, could prove to be a measure that adds purpose and efficiency to the way the SFO pursues cases. It could, however, turn out to be a muzzle on the SFO; preventing it acting in the way it wants and denying it a free hand when it comes to which cases it takes on and how it resolves them.

Green has taken a neutral stance on the NECC, indicating that we will have to wait and see how it affects the SFO. He has stated that the NECC's power over the SFO should be seen as nothing new, as the Director of the National Crime Agency (NCA) already has powers to direct the SFO to provide assistance. Green has also beaten the drum for anything that encourages cooperation between government agencies. He has, however, emphasised the need to preserve the SFO's independence.

Like everyone else, Green is in no position to accurately gauge how the NECC will affect the SFO. Cynics may argue that this would not have even been an issue if the SFO had been more successful under Green's tenure. That seems a little harsh. Under him, the SFO has achieved a lot. Some of those achievements, however, leave the impression that they could have been bigger or better.

Funding

Speaking to the Justice Committee last December, Green emphasised the point that he had never turned a case down because it could prove to be too costly. He pointed to the fact that he has investigated LIBOR while his predecessor had declined to do so. He also pointed to the fact that he had managed to secure what has become known as blockbuster funding – funds on top of the SFO's basic annual budget – to tackle some major cases as they have arisen.

It is also worth noting that when he took over the SFO, it was an organisation in disarray. His predecessor, Richard Alderman, was to be accused by the Public Accounts Committee of "shocking'' stewardship of its finances. It was Green who brought to an end the costly legal and financial fall-out from the catastrophic and misguided raids on the Tchenguiz brothers carried out under his predecessor's control.

Yet while obtaining blockbuster funding for some cases has to be seen as an achievement for Green, the fact that the SFO's total annual budget – its core budget plus blockbuster funding – is at its lowest for five years indicates a lack of success when it comes to securing the finances it needs. The core budget for 2017-18 is £35.7M plus £10M in extra funding. This is the first time since 2012-13 that its total budget did not exceed £50M. Whether this is a blip remains to be seen.

Even the most ardent supporter of the SFO's finances could only conclude that its funding has, at best, been stagnant this decade. As a result, it has often failed to retain its most talented lawyers and investigators because they can leave for better pay elsewhere – which has to affect the SFO's effectiveness. The question has to be asked, therefore, could or should David Green have done more to secure a bigger budget for the organisation he leads?

DPA's

On Green's watch, the DPA has been used to settle four cases. The most notable were concluded last year, when Rolls-Royce agreed to pay a £497M fine for bribery and corruption and Tesco paid £129M over its false accounting scandal. The Director has called the DPA a means of ensuring transparency by encouraging companies to self-report and cooperate with the SFO. He sees it as a way in which companies can be held accountable without them being convicted and possibly prevented from competing for public contracts. They are also a means by which the SFO can hold a company accountable without the time, effort and cost – not to mention the risk of losing – that comes with a prosecution.

So David Green can pat himself on the back if he feels the introduction of DPA's has been a success. There are those, however, who would argue differently. They see the DPA as a means of the big boys avoiding the prosecution that they should, by rights, have to face. Critics of the DPA see it as a means by which the wealthy can buy their way out of the trouble they find themselves in. For them, the DPA is not an instrument of transparency. If anything, they view it as a way for wealthy, guilty parties to sidestep the courts and come to a cosy agreement with the authorities.

Having only seen four DPA's completed, it is possibly too early to come to any definitive conclusion about the merits or otherwise of them. Much will depend on the future cases in which the SFO chooses to go down the DPA route. Only then can we really judge the true value of DPA's. It is also worth noting that the wheels had been set in motion for the introduction of DPA's before Green took up his position at the SFO, so he cannot be given full credit if they prove worthwhile.

Cooperation

Green is leaving his post at a time when uncertainty also surrounds the international aspect of the SFO's work. With Brexit looming, it remains to be seen how issues such as European arrest warrants, joint investigations teams, mutual legal assistance, the enforcement of confiscation and restraint orders and the UK's involvement with Europol develop.

It would be wrong to criticise the outgoing Director for not resolving such matters. After all, there is no way he could have singlehandedly been the architect of a rapidly-arranged post-Brexit European law enforcement regime. He has talked of the need to preserve current international arrangements or, at the very least, find credible, workable alternatives to them. It may be some time after David Green's departure before we learn what the UK's post-Brexit, European fraud investigation looks like and what, if any part, he played in shaping it.

Caseload

If Green is to depart with a feather in his cap, it is perhaps due to his commitment to taking on the big cases. While his predecessor fought shy of prosecuting over LIBOR, Green had no such qualms. This enthusiasm for the big cases has been complemented by his use of the blockbuster funding and the SFO's ability to offer DPA's when it believes one is suitable. We have, however, already outlined the possible shortcomings on both these aspects of the SFO's work. It must also be said that the SFO's prosecutions under its current Director have not been an unqualified success.

Speaking to the Justice Committee last year, Green pointed to the SFO's conviction rate of almost 70% under his tenure. This, however, does not paint the full picture. The conviction rate has fallen well below this figure at times during Green's reign. Less than two years ago, the SFO failed to secure the convictions of six bankers in relation to Libor and a nine-year investigation into a boiler room operation ended with two men being acquitted and the SFO being dubbed incompetent by one of the defence teams. It has secured the Libor conviction of Tom Hayes and gained guilty verdicts for two Barclays traders in relation to Libor. But it twice failed to secure convictions against two others.

Critics will also point to no changes being brought over the Forex scandal – a scandal which saw six banks pay fines totalling £6.6 billion and yet no one was held criminally liable.

Two months ago, the SFO was heavily criticised for its decision to pay £400,000 to a supposed expert witness in Libor trials who was, it has been claimed, texting friends for help. The SFO's use of the witness was described as a "debacle'' in the Court of Appeal. Families of three traders convicted over Libor have asked the Justice Committee to examine the SFO's "selection, retention and oversight'' of the witness.

As yet, that incident has yet to be fully resolved. It is one of a number of incidents which may, therefore, make us hesitate before placing that feather in the departing Director's cap.

It seems we may need some time before we can make a clear and accurate assessment of David Green's achievements...or lack of them.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.