The protagonists of 1914 were sleepwalkers, watchful but unseeing, haunted by dreams, yet blind to the reality of the horror they were about to bring into the world.”

Christopher Clark’s The Sleepwalkers retells the story of the outbreak of the first world war. Mapping a multipolar world enthralled by imperialism and paranoia, Clark refuses to pin the blame on a single power. Instead, he explains how political leaders narrowed the prospects for peace one misstep at a time, and sleepwalked into a global catastrophe that left around 20 million people dead.

Today, once more, our political leaders are stumbling through crisis after crisis to convince themselves that war is the only solution. The principal difference is that this time they are not sleepwalking into war. They are doing so with their eyes wide open.

For months, millions of us have demonstrated for a ceasefire in Gaza to stop the loss of life, end the perpetual cycle of violence and prevent a wider escalation. We have been ignored, maligned and demonised. Last week, Israel conducted missile strikes against Iran in a fast-widening conflict across the Middle East. Even without the involvement of more global players, the human, economic and environmental consequences of all-out war with Iran would be catastrophic for the entire world.

We need not imagine the worst-case scenario in order to put the brakes on. As the Israeli government weighed up its options in response to Iran’s attack on 14 April, bombs continued to fall on Palestinians in Gaza. Over the past few months, human beings have been forced to endure a level of horror that should haunt us for ever. Entire families have been wiped out – and survivors will face lifelong mental health consequences for generations to come. Neighbourhoods have been completely obliterated, strewn with corpses and limbs. Doctors are performing amputations without anaesthesia. Children are gathering sticks and leaves from the ground and fashioning “bread” from animal feed to stay alive. If the unfolding genocide of the Palestinian people does not already constitute a worst-case scenario, what does?

Back in October, many of us warned that we were witnessing the beginning of the total annihilation of Gaza and its people, and we pleaded with political leaders on both sides to call out war crimes that were being committed before their very eyes. Today, some politicians have finally started to backtrack, frightened by the electoral consequences of their inhumanity. If they had any integrity, they would weep for the 33,000 Palestinians who have been killed, starved or buried under the rubble by their moral and political cowardice.

Today, schoolchildren are taught about history’s worst crimes against humanity. They are asked to reflect on how these crimes could have possibly occurred. And they learn the names of political figures that endorsed or enabled such atrocities. In the near future, our history books will shame those who had the opportunity to stop this massacre but chose to cheer on war instead. They will be immortalised for their inability to treat Israeli and Palestinian lives with equal worth. They will be remembered for their failure to prevent genocide.

In the aftermath of horror, we need politicians with the ability and willingness to actively facilitate de-escalation and diplomacy. Instead, their thirst for war is endangering us all. Our government could have called for a ceasefire from the very beginning. Instead, it paved a path to escalation by launching military strikes against Yemen, one of the poorest countries in the world, and doubling down on the policy of arms exports to Israel, fuelling a wider global arms industry that profits from death. All with the support of His Majesty’s official opposition, signalling a continuation of an unethical and inconsistent foreign policy that treats some people as innocent civilians and others as collateral damage.

Hundreds of thousands of us continue to march because human beings continue to die – and we will be there once again in London on Saturday, for another National March for Palestine. We will be demonstrating for a ceasefire and for the only path to a just and lasting peace: the end to the occupation of Palestine. We are guided by hope, not hate. Our demonstrations are made up of people of all ages, faiths and backgrounds, united in a desire to end human suffering. And we are part of a wider movement that wants to see an end to all wars: in Ukraine, Yemen, Sudan, West Papua, the Democratic Republic of the Congo and elsewhere.

Many of us have spent our entire lives defending human rights for everyone, everywhere, often in the face of great opposition. Our critics know this. What they really oppose is our desire to build a more equal, sustainable and peaceful world for all.

Real security isn’t destroying your neighbour, it’s getting on with your neighbour. It’s having enough food on the table, a roof over your head, and a sustainable planet. Political leaders may take pride in their militaristic jingoism, knowing that it’s somebody else’s children who will pay the price. The truth is, however, that their thirst for war is endangering us all. If our politicians care about the legacy they leave behind, they may want to ask themselves: if they fail to pave a path to peace, who will be around to remember them?Email