The UK "is serious" about its commitments to support Yemen's development and humanitarian needs, international development minister Alan Duncan said as he announced a £35 million programme to tackle malnutrition in the country.
Mr Duncan stressed "others must now follow this lead" as he revealed details of the assistance package to improve nutrition for 1.65m women and children in Yemen during a brief visit to Sana'a.
The money from the UK will be used to help 100,000 children suffering from malnutrition
The UK funding will amount to £35m over the next three years and is the first major new programme from the £196m of support from 2012 to 2015, which the UK announced at the Donors Conference in Saudi Arabia in September.
A subsequent Friends of Yemen meeting in New York last month saw total international funding pledges exceed $7.8 billion.
Britain's support will help Unicef work with Yemen's government to address the "root causes" of malnutrition over the long term, the Department for International Development said.
The aid will focus on improving nutrition in mothers and children under five in 60 of the most deprived and conflict affected districts in the eight governorates in Yemen in greatest need.
It will be spent on assisting Unicef in treating acute malnutrition in 100,000 children and delivering nutritional counselling and micronutrient supplements for 750,000 women, plus improving water, sanitation and hygiene facilities in 300 schools helping 250,000 children.
Other priorities will include providing vitamin A supplements and/or de-worming treatment for 550,000 children, offering counselling to help improve infant feeding practices for 130,000 parents and training 12,000 community health volunteers to recognise and treat malnutrition.
Mr Duncan said Yemen had made "fragile but tangible gains" in the last few months in the wake of elections, adding: "Now is the time to invest in the future, in the children who will help to rebuild and stabilise this country over the next 20 or 30 years."
Nearly half of the younger generation faced "stunted growth and delayed mental development" as a result of malnutrition, while more than a quarter of a million more were at "immediate risk of death", he said.
Calling on donors to deliver, Mr Duncan added: "The funding pledges made at the Friends of Yemen two weeks ago were a vital step forward, but donors must make good on these promises and show that they're standing by Yemen for the long haul.
"The launch of this major new programme shows that the UK is serious about commitments made in Riyadh and New York, but others must now follow this lead and provide predictable, long-term funding.
"Without that, agencies can't commit to tackling the root causes of malnutrition in case their funding is stopped half way through - resulting in time and money down the drain and more lives lost."