Last month a lawsuit spanning 35 pages was filed with the Philadelphia Court of Common Pleas, with O’Neill Properties Group claiming that lender’s US subsidiary, Citizens Bank, reneged on its financing commitments in redeveloping a $700 million steel plant site.

The property group claims that the state-controlled bank jeopardised the project, used sham defaults and attempted to collect on a reported $180 million of loans, due to its own liquidity crisis.  

Seeking $4 billion in damages suffered as a result of the bank’s actions, as well as $4 billion of punitive damages, O’Neill has said Citizens Bank “embarked on a campaign to raise and recover capital by any means necessary – whether lawful or not.”

An RBS spokesman has said that the bank intends to vigorously defend the action.