British forces helping transport ammunition to Kurdish forces in Iraq

Link to video: Iraq: Britain will 'play role' in arms transport, says David Cameron

Britain is helping transport Soviet-era ammunition from eastern European countries to Kurdish forces fighting jihadists from the Islamic State (Isis) in northern Iraq, David Cameron has said.

In a sign of Britain's growing involvement in Iraq, the prime minister also confirmed that British forces would also play a leading role in airlifting Yazidi refugees from Mount Sinjar. Chinook helicopters deployed to the region are expected to join a US-led operation in the coming days to airlift the refugees.

The PM's remarks, when speaking in Downing Street after he returned to work from his Portuguese holiday a day earlier than expected to take direct command of Britain's response to the Iraq crisis, prompted an intensification of calls for a return of parliament. Sir Menzies Campbell, the former leader of the Liberal Democrats, said that MPs should debate the decision to put British forces in harm's way in Iraq.

Campbell spoke out after the prime minister responded to a French decision to arm Kurdish forces by saying Britain would help to restock Kurdish supplies by transporting ammunition. The RAF will be flying in Soviet-era weapons from former Warsaw pact countries in eastern Europe to the Kurds who are trained in the use of weapons which originated from the Soviet Union. The Kurds have not requested British weapons.

From Downing Street, Cameron told the BBC: "We do support the Kurds and we should continue to support the Kurds. In terms of the ammunition they are getting – Britain is going to be playing a role in helping to get that to them. What they want is ammunition and weapons like they have been using. That is what is being delivered to them and Britain is playing a role in helping to make sure that happens."

The prime minister said that Britain would play a leading role in helping to airlift refugees from Mount Sinjar. He said: "We need a plan to get these people off that mountain and get them to a place of safety. I can confirm that detailed plans are now being put in place and are underway and that Britain will play a role in delivering them. I think the first thing is to deal with this desperate humanitarian situation, with people who are exposed, starving, dying of thirst on this mountainside – getting them to a place of safety."

Cameron said he had no current plans to recall parliament. He said: "This is a humanitarian operation that Britain is involved in so I don't think it is necessary to recall parliament for that. But of course I always keep this issue under review and were things to change then obviously that is something that could be done."

But Campbell told Sky News: "We have heard from the prime minister that we are increasing our obligation. It is certainly still part of the humanitarian effort. But if we are taking part in a rescue operation that can only be through the use of helicopters – then helicopters, by their nature, are subject to the risks from surface-to-air missiles. We know that the Isis jihadis have captured some of those.

"When you are putting troops or any personnel into harm's way you really do have an obligation to come to the House of Commons and to explain. I think it is in the interests of the government to come to the House of Commons and explain. For the moment at least the government has a story to tell. We are helping with the humanitarian effort, we are helping with the intention to provide more weapons to the peshmerga – helping to move these weapons."

The PM made his remarks after chairing a meeting of the government's emergency Cobra meeting as the government comes under renewed pressure to join the US in launching military strikes against Isis forces.

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 were also inside the packages. There have now been five successful drops over three nights.

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.

"Sending humanitarian aid is right but if we are leaving the vulnerable unprotected from the military terror of the Isis forces then our help is superficial."