A bankrupt Taiwanese shipping magnate is suing the Royal Bank of Scotland and its former chief executive Fred Goodwin after alleging billions of dollars were syphoned from his accounts.

Nobu Su - who has been described as "colourful" and "enigmatic" - launched his lawsuit in a court in Singapore this week after years of tirades against financial institutions.

Mr Su says the bank, Mr Goodwin and two other former employees “conspired to injure him by unlawful means” between 2007 and 2009, a period that covers the near-collapse of RBS.

He argues that Mr Goodwin - then Sir Fred before he was stripped of his knighthood - "breached their fiduciary duties to the bank and were negligent in protecting his business interests".

Mr Su claims RBS "fraudulently misled him of his true commercial position and consistently issued inaccurate statements with improper and erroneous margin requirements, resulting in considerable loss and damage to his business interests".

He is understood to be alleging that $3.6bn was removed from his account without permission.

Mr Su's shipping company TMT file for bankruptcy protection in the United States in 2013. He is understood to be involved in several other court actions.

The entrepreneur expanded his business quickly from his base in Taiwan as trade with China boomed.

His complaints against RBS date back years. In 2008, Labour MP Pat McFadden, who was on the Banking Standards Commission and the Treasury Select Committee, wrote to the Financial Conduct Authority and RBS on Mr. Su's behalf.

The Singapore claim names the defendants as: The Royal Bank of Scotland PLC (trading as RBS Greenwich Futures), The Royal Bank of Scotland PLC (Singapore Branch), Fred Goodwin, Neena Birdie and Marie Chang.

RBS has not been commenting on the case.