It would appear from numerous media reports that the final straw as far as Fredriksen was concerned was the decision by the Norwegian government to make individuals resident for tax purposes if they spend on average more than 90 days a year over a three year period, down from six months.

At least one of Fredriksen's businesses, Hemen Holding, an investment company through which he runs Frontline Ltd, is already registered in Cyprus. Sea Tankers in Limassol is also one of his companies. The top rate of personal income tax in Cyprus is levied at 30% on income in excess of CYP20,000 (EUR44,650).

"If we want people and capital out of Norway, this is the way to do it. The 90-day rule was made to threaten Fredriksen back to Norway," friend and fellow shipping businessman Herbjorn Hansson told the Norwegian daily Aftenposten. In reality however, Hansson said that Fredriksen has been "hunted" out of the country by Norway's overbearing authorities.

The country's Prime Minister, Jens Stoltenberg, appeared unmoved by arguments that Norway's high tax regime was scaring away what Hannson called "net contributors to social construction."

"It hasn't crossed my mind to adjust the tax system so that John Fredriksen can avoid taxes," he remarked in a report by NTB.

In any case, Stoltenberg noted, Fredriksen has not lived or paid taxes in Norway for many years; it is said that Fredriksen currently runs his business empire from his GBP40 million west London home.

Fredriksen's route to fortune began as a trainee in a shipbrokering company, and he is now the world’s largest tanker owner, with more than 70 oil tankers and major interests in oil rigs and fish farming.

He made his fortune during the Iran-Iraq wars in the 1980s when his tankers picked up oil at great risk and huge profits. His biographer decribed him as "the lifeline to the Ayatollah."

In 2005 Forbes ranked Fredriksen 160th in the world with $3.4 billion but by 2006 he had jumped to 116th place with $5 billion. The unofficial number is closer to $7 billion.