The government is coming under renewed pressure to allow the British military to protect Iraqi civilians after the intervention of a former defence secretary and former military figures.
As more aid was delivered to help thousands of people trapped on Mount Sinjar in the north, Liam Fox attacked the “catastrophic complacency” of world leaders.
His words came as the international development secretary, Justine Greening, confirmed on Tuesday that a third round of successful UK airdrops had taken place.
The supplies included two RAF C-130 consignments containing 2,640 reusable water purification containers filled with clean water.
More than 500 shelter kits to provide shade in temperatures higher than 40C (104F) were also inside the packages.
There have now been five successful drops over three nights.
Meanwhile, another 130 US troops have arrived in Iraq on what the Pentagon described as a temporary mission to assess the scope of the humanitarian crisis faced by thousands of displaced civilians trapped on Sinjar.
Fox wrote in the Daily Mail: “The idea that this is not our problem is wishful thinking at best, and catastrophic complacency at worst. The US government has made a belated, but welcome, decision to use American air power to hit Isis bases. We should be willing to do the same if asked.