Gunvor Group chief executive Torbjorn Tornqvist has revealed a dismal forecast for the refining sector, but said its ships have been making plenty of money this year.

In an internal memo to staff seen by Bloomberg, the billionaire founder of the trading giant said he expected "brutal" refining margins to persist for many years.

Gunvor has previously said it is considering shutting down its refinery in Antwerp, as it continues to lose money.