UBS initiated a root-and-branch review of compliance practices in 2007 following unauthorised trading on its UK wealth management division’s Africa desk, a UK tribunal has heard.

The revelation of another incident of rogue trading in London came from the barrister for one of the bank’s senior executives yesterday, just days before Kweku Adoboli, a former UBS employee charged in September with four counts of fraud and false accounting, is scheduled to enter a plea in the case that caused a $2.3bn trading loss.

The Financial Services Authority maintains that John Pottage, UBS’s former UK chief executive of wealth management, should have acted sooner to spot “serious flaws” in the bank’s risk management. It has imposed a ￡100,000 fine, which he is challenging, arguing that he took all reasonable steps to eradicate “sloppy” compliance after he was made chief executive in 2006.