FILE PHOTO: A boat sails after approaching to the boarding ladder (L) of the Iranian oil tanker Grace 1 as it sits anchored after it was seized in July by British Royal Marines off the coast of the British Mediterranean territory on suspicion of violating sanctions against Syria, in the Strait of Gibraltar, southern Spain August 14, 2019. REUTERS/Jon Nazca

LONDON (Reuters) - The Iranian tanker Grace 1 will likely be allowed to leave Gibraltar following a court decision which is due on Thursday, a source told Reuters.

A court in Gibraltar will on Thursday decide whether to extend the detention of the ship which was seized on June 4.