Macfarlanes is among the firms advising on the Serious Fraud Office's (SFO) investigation into U.K. petrol giant Greenergy, announced earlier today (May 16).

The regulator said in a statement that it has opened a joint investigation with Dutch authorities concerning aspects of biodiesel trading at Greenergy and various third parties.

It added that searches were conducted last month at five sites across the U.K. and additional sites in the Netherlands and Belgium. Four people were arrested in relation to the investigation, who have been released without charge.

Greenergy is one of the largest suppliers of diesel and petrol in the U.K.

Macfarlanes head of corporate crime and investigations Neill Blundell is leading the firm's team advising the Greenergy on the matter, according to one person with knowledge of the situation. Blundell joined Macfarlanes last year to launch a white-collar practice at the outfit. Dan Lavender, a financial services litigation and investigations partner, is also advising.

Other business crime specialist firms have also lined up to take on elements of the investigation.

Kingsley Napsley partner and criminal litigation head Louise Hodges has been appointed to the case, according to the person with knowledge of the matter, alongside partners at corporate crime specialists BCL and Blackfords.

BCL corporate and financial crime partner Julian Hayes, who also specialises in computer misuse offences, surveillance and data protection law is advising, as is Blackford financial crime co-head Gary Bloxsome, one person close to the situation told Legal Week.

Serious fraud and criminal defence specialist Janes Solicitors has also been appointed to the case, with its senior partner and head of serious and complex fraud and taxation David Janes leading the firm's team, according to the person with knowledge of the matter.

Greenergy said in a statement: "On Tuesday April 30, 2019, Greenergy became aware of an ongoing investigation into aspects of its biodiesel trading business and various third parties as part of a coordinated operation involving the U.K. and Dutch authorities.

"The company takes these matters very seriously and is engaging and cooperating fully with the authorities. As this is an ongoing investigation, we are not permitted to give any further details at this time."