Ministers have announced a doubling of aid to Sudan in response to deepening concern that the country is heading towards a famine worse than the one witnessed in Ethiopia 40 years ago.

Assistance worth £113m has been agreed for the war-torn state and neighbouring countries amid fears that Sudan’s death toll through starvation could ultimately exceed the Ethiopian famine that, according to UN estimates, caused a million deaths between 1983 and 1985. A ruinous civil war between the Sudanese army and the paramilitary Rapid Support Forces (RSF) has seen starvation repeatedly used as a weapon, with aid deliveries blocked by both sides.

The £113m package means Sudan will be among the highest recipients of UK bilateral foreign aid. It reflects its status as not only the worst humanitarian crisis in the world – but one that is becoming a humanitarian catastrophe of historic proportions. Sudan will be receiving roughly the same as Afghanistan did last year, though critics will point out the amount is still less than half what the UK gave Ukraine. Tomorrow the UK will push a draft UN security council resolution calling for the protection of civilians and unrestricted passage of aid in Sudan.

During a visit to the UN security council in New York, foreign secretary David Lammy will urge the Sudanese Armed Forces (SAF) to keep the critical Adré border crossing with Chad open indefinitely and for the removal of restrictions that have curtailed the amount of aid passing through.

“We cannot deliver aid without access. Starvation must not be used as a weapon of war and we can only stop this famine if every border crossing and route is open, accessible and safe,” said Lammy. UK officials hope the increased aid will support more than a million people affected by Sudan’s catastrophic conflict.

Alarm is intensifying, however, over the ramifications of the ongoing fighting in el-Gezira state, Sudan’s agricultural heartland, which could dramatically limit food supplies.

If no significant improvements materialise to boost the supply of food and humanitarian help, officials fear that Sudan’s death toll could end up running into the millions.

On Friday a study found that the death toll from Sudan’s civil war is already much higher than previously reported. Of more than 61,000 people who have died in Khartoum, researchers found that only 26,000 were killed through violence, with the leading cause of death across Sudan identified as preventable disease and starvation.

Evidence also emerged last week that hundreds may have died in a cholera outbreak in the besieged town of al-Hilaliya in el-Gezira state. The RSF surrounded the town last month, home to tens of thousands of locals and displaced people.

Despite the scale of the crisis facing Sudan, UN agencies recently reiterated the urgent need for additional funding. Currently the UN’s £2.14bn Sudan humanitarian appeal is only 57% funded, posing “significant challenges” to sustaining necessary relief efforts. More than 500,000 people in Darfur, west Sudan, are in famine conditions which is likely to spread. Throughout the country, 25 million are reliant on aid.