International Development Secretary Priti Patel has hailed the opening of a "vital" new humanitarian corridor to South Sudan, which she said could help feed 300,000 people.
The East African country is set to benefit from a new border crossing from neighbouring Sudan, which will deliver emergency food assistance to thousands of people at risk of famine due to the ongoing civil war.
One million people are on the brink of starvation and famine has been declared in two counties in South Sudan, where fighting has raged since 2013.
Ms Patel said: "This world food programme delivery contains enough food to feed 300,000 people for three months.
"This is vital ahead of the rainy season, which renders roads impassable and will give thousands of people the chance to stay alive.
"UK support is delivering urgently needed food, water and medicine for millions of people in South Sudan, as well as food and shelter for refugees crossing the border into Sudan.
"We will continue to work with the government of Sudan and others in the region to ensure aid reaches those in need.
"Without vital assistance, famine and malnutrition will spread across South Sudan and more people will die."
Britain will give at least £100 million this financial year to South Sudan, which is facing one of the world's largest humanitarian crises.