The biggest shareholder in UBS broke its silence about the $2.3bn rogue trading scandal that has engulfed the Swiss group, criticising “lapses” in the bank’s controls ahead of a pivotal UBS board meeting in Singapore.

Government of Singapore Investment Corporation (GIC), Singapore’s sovereign wealth fund, was already sitting on a substantial loss on its 6.4 per cent stake in UBS before last week’s shock disclosure that a 31-year-old trader on the bank’s “Delta One” desk in London allegedly lost billions by taking unauthorised futures positions.

Oswald Grübel, UBS’s embattled chief executive, met GIC as the bank’s board gathered to review the implications of the scandal, and to consider sweeping changes to its business model in a long-scheduled meeting timed to coincide with the Singapore Grand Prix.