Secretary-General Ban Ki-moon has appointed British lawmaker Stephen O'Brien, who has more than 20 years experience in international development, as the next U.N. humanitarian chief.

Ban announced Monday that O'Brien, a lawyer who was born in Tanzania and also has wide experience in business, will succeed Valerie Amos as undersecretary-general for humanitarian affairs and emergency relief coordinator.

O'Brien has served as British Prime Minister David Cameron's special representative for the Sahel since 2012 and won the 2014 Champions Action Award for his leadership in mobilizing campaigns against malaria and neglected tropical diseases.

The U.N. chief expressed his "utmost gratitude" to Amos, a member of Britain's House of Lords, for her outstanding service to the U.N. in tirelessly advocating for the world's neediest people.