The Royal Bank of Scotland (RBS) has launched a legal challenge to have Cooke Young & Keidan (CYK) removed as lawyers to Property Alliance Group (PAG), which is bringing a major dispute against the bank.

The bank filed for an injunction on Wednesday (27 January) to prevent the firm from continuing to act for the property investment company over alleged issues of conflict.

CYK is representing the property investment company in its £30m Libor rigging and derivatives mis-selling claim against RBS, scheduled to be heard in May.

Following a hearing this week RBS served an injunction against the litigation boutique over its hire of a junior associate who used to work at Clifford Chance.

The bank said the associate had access to confidential documents concerning RBS during his time at Clifford Chance, The Lawyer understands.

In a statement to The Lawyer, the bank said: “In taking this action RBS is seeking to protect confidential and sensitive privileged information that it believes is at risk of misuse.”

The junior associate trained and then worked at at Clifford Chance between 2011 and 2014, leaving to join offshore firm Carey Olsen in March 2014.

Clifford Chance ran an independent review into RBS’s controversial global restructuring group (GRG) in 2013, finding no evidence the bank was guilty of systematically running small businesses into the ground to make a profit.

The results of the report were at odds with the findings of the Lawrence Tomlinson report into GRG one year earlier. The magic circle firm’s findings have been thrown into question by CYK in the case following an application by RBS to have all reference to it removed from its defence.

CYK said in a statement: “Whilst we have only very recently been served with these proceedings, we believe that the application is without merit and intend to defend it. As this is an ongoing legal matter, it would not be appropriate for us to comment further at this time.”

RBS is understood to have retained Dentons on the injunction application. Dentons partners Richard Caird and Sam Coulthard are handling the bank’s defence in the battle with PAG.

CYK has instructed PCB Litigation partner Trevor Mascarenhas to defend the legal challenge.

PAG’s case against RBS is one of the most advanced Libor-rigging cases before the courts. Following an application by RBS earlier this month the case will be moved from the Chancery Division to the Financial List.

The claim alleges the bank’s misconduct went far beyond what has been made public by regulators and say it made fraudulent misrepresentations about Libor at a time when the bank’s senior executives were aware of problems with the integrity of the benchmark.

PAG v RBS featured in The Lawyer’ Top 20 Cases 2016.