Caroline Anning from the charity Save the Children has warned the situation in South Sudan is similar to the east African famines in the 1980s.
Speaking to ITV News' Dan Rivers she said: "If it continues and we can't get the help we need, we could be looking at a catastrophic famine."
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The chancellor now faces the prospect of forming a minority government or calling for a snap election.
The 73-year-old said a return is unlikely "given the politicised atmosphere that seems to have afflicted our set."
Chancellor Philip Hammond said the UK will make a financial proposal to the EU in the next three-and-a-half weeks.