Rohingya refugees living in crowded conditions in Bangladesh face an “unprecedented” threat from an imminent monsoon that should sound alarm bells among the international community, David Miliband has warned.

The former UK foreign secretary has completed a two-day visit to Bangladesh to see the border camps at Cox’s Bazar, and in an interview with The Independent said 700,000 displaced Muslims from Myanmar faced “a natural crisis on top of a clearly man-made one”.

The UN has said Myanmar’s Rohingya appear to have been victims of a “textbook case” of ethnic cleansing, since the scale of violence in the region shocked the world in August 2017.

But Mr Miliband’s call to action comes at a time when international focus on the Rohingya crisis has waned. The US under President Donald Trump has cut its refugee resettlement programmes by three-quarters, he notes, while the UK has been so “systematically diverted by the Brexit trauma” as to limit its ability to make diplomatic interventions.

“The danger here is that people forget about this crisis,” he said. “Because a country next door has admitted them, the rest of the world thinks that it isn’t their problem.”

Justin Trudeau, the Canadian prime minister, has invited his Bangladeshi counterpart, Sheikh Hasina, to attend the G7 meeting in Quebec this week, and Mr Miliband – who now leads the International Rescue Committee (IRC) charity – said it was an opportunity for politicians to “provide answers to anger rather than just articulating anger”.

Clouds are now gathering over the bamboo and tarpaulin-covered shacks that make up most of the Cox’s Bazar camp network. When the monsoon comes, it will bring up to four months of heavy rain, turning the camp’s makeshift highways into rivers and, aid agencies fear, causing widespread mudslides where the landscape has been completely denuded of trees.

The IRC has been working to set up mobile healthcare units for when the camp infrastructure inevitably falters, and the UN has distributed 80,000 “tie-down kits” – hammers, nails and rope so refugees can literally tie down their makeshift homes.

But with a gap between funding and what would be needed to protect a “uniquely vulnerable” population, Mr Miliband said there is only so much they can do.

“You can predict a monsoon but you can’t predict a cyclone,” he said. “Obviously Bangladesh has a whole history of securing and protecting its own population at the time of cyclones, but it has never had to do that for this number of refugees.”

On his visit to the camps, Mr Miliband met children traumatised by what they had witnessed, as well as families who still had relatives back in Myanmar and who feared for their safety.

“One woman told me her uncle couldn’t leave with them because he is too old. She just said, ‘He is going to die, and I’m never going to see him again.’ It really is a tragic and traumatic situation.”

Rohingya crisis in photos Show all 15 1 /15 Rohingya crisis in photos Rohingya crisis in photos Rohingya refugees are reflected in rain water along an embankment next to paddy fields after fleeing from Myanmar into Palang Khali, near Cox’s Bazar, Bangladesh November REUTERS Rohingya crisis in photos Rohingya refugees scramble for aid at a camp in Cox’s Bazar, Bangladesh REUTERS Rohingya crisis in photos Betel leaves cover the face of 11-month-old Rohingya refugee Abdul Aziz whose wrapped body lay in his family shelter after he died battling high fever and severe cough at the Balukhali refugee camp near Cox’s Bazar, Bangladesh, December REUTERS Rohingya crisis in photos An exhausted Rohingya refugee fleeing violence in Myanmar cries for help from others crossing into Palang Khali, near Cox’s Bazar, Bangladesh November REUTERS Rohingya crisis in photos Mohammed Shoaib, 7, who was shot in his chest before crossing the border from Myanmar in August, is held by his father outside a medical centre near Cox’s Bazar, Bangladesh REUTERS Rohingya crisis in photos Rohingya refugees try to take shelter from torrential rain as they are held by the Border Guard Bangladesh (BGB) after illegally crossing the border, in Teknaf, Bangladesh REUTERS Rohingya crisis in photos Rohingya refugee children fly improvised kites at the Kutupalong refugee camp near Cox’s Bazar, Bangladesh REUTERS Rohingya crisis in photos Smoke is seen on the Myanmar border as Rohingya refugees walk on the shore after crossing the Bangladesh-Myanmar border by boat through the Bay of Bengal, in Shah Porir Dwip, Bangladesh REUTERS Rohingya crisis in photos People gather under heavy rain around bodies of Rohingya refugees after the boat they were using to flee violence in Myanmar capsized off Inani Beach near Cox’s Bazar, Bangladesh REUTERS Rohingya crisis in photos The remains of a burned Rohingya village is seen in this aerial photograph near Maungdaw, north of Rakhine State, Myanmar REUTERS Rohingya crisis in photos Rohingya refugees cross the Naf River with an improvised raft to reach to Bangladesh in Teknaf, Bangladesh REUTERS Rohingya crisis in photos A security officer attempts to control Rohingya refugees waiting to receive aid in Cox’s Bazar, Bangladesh REUTERS Rohingya crisis in photos Hamida, a Rohingya refugee woman, weeps as she holds her 40-day-old son after he died as their boat capsized before arriving on shore in Shah Porir Dwip, Teknaf, Bangladesh REUTERS Rohingya crisis in photos Rohingya siblings fleeing violence hold one another as they cross the Naf River along the Bangladesh-Myanmar border in Palong Khali, near Cox’s Bazar, Bangladesh REUTERS Rohingya crisis in photos An exhausted Rohingya refugee woman touches the shore after crossing the Bangladesh-Myanmar border by boat through the Bay of Bengal, in Shah Porir Dwip, Bangladesh September Reuters

Mr Miliband said that since he left British politics in 2013, three years after he lost a fight for the Labour party leadership against his brother Ed, the IRC has grown to the point where it provided assistance to 27 million people last year – of which he is “immensely proud”.

He says it is nonetheless up to governments to ultimately take action in crises like the one facing the Rohingya, adding: “Humanitarian aid can staunch the dying but it takes politics to stop the killing.”

Progress on a political solution in Rakhine has stalled since the new flare-up in violence last year, when the fighting distracted from what could have been a breakthrough report by an independent commission chaired by former UN secretary general Kofi Annan.

The UK has “a very good record” in terms of financial aid to the Rohingya, Mr Miliband said, but like other countries has suffered from a “tragic hacking back” of programmes to take in refugees.

Britain has also failed to make significant diplomatic inroads with the government of Aung San Suu Kyi in spite of its long-standing and close ties to both her and Myanmar as a country.

Mr Miliband said the UK appeared to have “other things on our plate”, adding that during his time in government, British clout in Myanmar was “substantially magnified, augmented and supported by our membership of the European Union”.

“Around the world people are wondering what is the future of UK foreign policy,” he said. “And they are clear that bilateral [UK-Myanmar] foreign policy can never make up for an absence of multilateral foreign policy.”

Mr Miliband’s own family came to the UK as refugees from Nazi-occupied Belgium, and, in appealing to the “conscience of the world” to step up and help displaced people, he said there were “important parallels” to be drawn between the contemporary refugee crises and those of the early 20th century.