Labour deputy leadership hopeful Richard Burgon has come under fire from his own side after proposing an overhaul of party rules to ban Labour from supporting future wars without putting it to a vote by members.

Leadership candidate Lisa Nandy said the stance would have made Labour’s former foreign secretary Robin Cook – whose “foreign policy with an ethical dimension” saw him oversee a military intervention to end civil war in Sierra Leone – feel “ashamed”.

And party education spokesman Steve Reed urged Burgon to ditch his “dangerously anti-democratic” proposal immediately, warning: “We will end up in a very dark place if we take major issues of national security, war and peace out of the hands of our elected representatives and hand them to unelected members of any party.”

But Jeremy Corbyn said the idea had "a lot of merit", and told Burgon in a video conversation: "I do think it's important that we as a party are seen to be a party of peace, a party of human rights, a party of social justice around the world."

Mr Corbyn said: "If we are to avoid the wars of the future, we have got to look at how we got involved in Afghanistan, Iraq and Libya and look at the consequences."

Meanwhile, left-wing leadership candidate Rebecca Long-Bailey described the idea as “interesting”, though she cautioned that it may not be practical to take votes at times of military crisis

In a speech on Wednesday, the shadow justice secretary vowed to change the Labour constitution to give members a veto on military action supported by the leadership – except in cases of national emergency or when there is UN backing.

Unveiling his “Labour Peace Pledge”, Mr Burgon recalled the “disastrous and illegal” Iraq War and vowed that Labour members would never again have to endure “the shame of having to protest ‘Not in my name’ against their own party”.

He said: “Labour remains scarred by the experience of the Iraq War – for many it is sadly the single act for which the last Labour government is most remembered.

“It was a conflict opposed by most Labour Party members at the time.

“Jeremy Corbyn rightly apologised for Labour’s role in the disastrous and illegal war at the time of the publication of the Chilcot Report in 2016.

“But even since Iraq, Labour mistakenly backed the intervention in Libya, which has had catastrophic consequences for that country, and contributed to a massive refugee crisis.

“These interventions were supposed to have made us safer from terrorism. Tragically, they have failed in that objective too.”

Mr Burgon demanded that Labour supports foreign policy that is “robustly independent” of the United States and argue for the “explicit backing” of party members for any military intervention

But Ms Nandy hit out at the proposal for a party members veto on military action, saying: “I can’t disagree with him more.”

Answering questions after a speech in Worksop, Ms Nandy said: “I have to say that I think Robin Cook would be ashamed of where we may end up as a party

“At times in our history there have been moments when we have had to stand up and go to protect people all over the world.

“In Sierra Leone and Rwanda, those people couldn’t wait for us to go and ballot Labour Party members. I think everyone in this party understands that.

“We have a responsibility to protect and we have obligations to people outside our borders and that’s the kind of Labour Party I will lead.”

Lisa Nandy: ‘I can’t disagree with him more’ (AFP/Getty)

Mr Burgon's rival for the deputy leadership, Ian Murray, said his peace pledge plan was a "folly" which would leave Labour in permanent opposition.

“Part of the reason we lost the last two elections is because people didn’t trust our leadership when it came to national security," said Mr Murray. "This is the worst possible way to address that problem.

“If we are to be a credible government, we have to accept that decisions on military action are key decisions for government ministers to take, in possession of full information which will rightly not always be in the public domain."

Former MP Anna Turley, who lost her Redcar seat in December, was more pithy in her two-word response to the Burgon proposal on Twitter: “Jesus wept.” And Bermondsey and Old Southwark MP Neil Coyle said: "What horse s***. We are representatives, not delegates. If you want SWP then vote for them. Leave Labour alone."

Ms Long-Bailey said she wanted to discuss the plans with Mr Burgon, telling ITV’s Peston: “We need to see the details because clearly in matters of war, decisions need to be taken very quickly.

“Whether it’s practical to be able to do that is one thing, so I’ll have to see what he means by that.

“But in terms of democratising the party, that’s something I’m strongly in favour of and I’ve been talking about that quite a lot in the campaign.”

Mr Burgon is up against shadow cabinet colleagues Dawn Butler and Angela Rayner, the clear frontrunner, on the ballot paper for the deputy role.

Mr Murray and shadow sports minister Rosena Allin-Khan are scrambling to make up ground as both face being knocked out before the final round unless they win enough support from affiliated groups or local parties.