Britain soldiers are believed to have been told to "save the last bullet for yourselves" if they fear they are in danger of being taken hostage by the terror group.
The UK's force were flown into the Middle East last summer, as ISIS terrorists began to take control of large parts of Iraq, adding to their territory in Syria.
Reports of an order for Britain troops to "fight to the last man" rather than be taken captive by militants follows the horrifying murder of a Jordanian fighter pilot, who was burned to death by the ISIS.
"They know there is virtually no chance of being rescued.
“Everyone taking part in the Iraq mission knows the risks.