The Serious Fraud Office (SFO) has defended its prosecution of six ex-brokers accused of helping convicted trader Tom Hayes manipulate bank rates after five of the group were acquitted today.

The jury continues to deliberate charges against a sixth.

Colin Goodman, Danny Wilkinson, Noel Cryan, Terry Farr and James Gilmour were found not guilty at Southwark Crown Court (pictured) of conspiracy to defraud related to the manipulation of the London interbank offered rate (Libor). Darrell Read awaits his verdict.

The acquittals will be read as a setback for the SFO, which had enjoyed a run of successful prosecutions and ended 2015 with its first plea-deal deferred prosecution agreement in a high-profile bribery case.

Matthew Frankland, partner at Byrne and Partners, acted for Wilkinson. Frankland said: ‘The prosecution seemed not to understand the complexities of the case, including the hedging of trades, the commission earned by brokers and the general banker-broker relationship.’

He added: ‘Ultimately, there is a hypocrisy in charging brokers. Brokers do not work for banks, they play no part in the Libor submission process and are not and never were regulated by the BBA [British Bankers' Association] in relation to their Libor predictions.’

Director of the SFO David Green QC said: ‘The key issue in this trial was whether these defendants were party to a dishonest agreement with Tom Hayes. By their verdicts the jury have said that they could not be sure that this was the case. Nobody could sensibly suggest that these charges should not have been brought and considered by a jury.’

Christopher David, white collar crime lawyer at international firm Wilmer Hale, added: ‘Any perceived blow may be softened by the fact that they [SFO] have already secured the conviction of their primary target, Tom Hayes, and this trial was always considered, informally, as secondary to the Hayes trial.’

Hayes, former trader at UBS Group AG and Citigroup Inc, was jailed with a 14-year sentence in August 2014, although it was reduced on appeal to 11 years. Defendants acquitted in the second Libor trial worked for Prebon Plc and RP Martin Holdings Ltd. Read worked for ICAP.