“I voted to stay but it didn’t really turn my juices on,” he admitted.
What motivated him to chair the Best for Britain campaign to “shift” public opinion was his “dismay” at Government “chaos” – and the “powerful” anger of young people, including his own four children.
The 64-year-old peer was born in England to the son of a South African exile from the apartheid regime.
He went to Cambridge University before working in Thailand for the United Nations refugee agency and as a political correspondent with The Economist magazine.
He went on to forge a formidable reputation as a Washington-based political consultant advising foreign governments and politicians from South America to Asia.
After a spell as vice-president of the World Bank, he moved back to the United Nations in senior roles and coordinated its response to the 2004 Indian Ocean tsunami.
He eventually became UN deputy secretary-general, where he sparred with a hostile White House.
In 2007 he moved back to London when Labour Prime Minister Gordon Brown gave him a seat in the House of Lords and the job of Foreign Office minister responsible for Africa, Asia and the UN, as part of his “government of all the talents”.
The new peer had the right to attend Cabinet and – more controversially – the use of a grand grace-and-favour apartment in Whitehall for himself and his family.
In July 2009 he quit as a minister, citing personal and family reasons.
He went on to take a series of consultancy, company and academic roles.
His involvement with Best for Britain continues his long association with Hungarian-born financier George Soros, one of the group’s major donors.
Lord Malloch-Brown has previously been involved with Soros organisations and committees and reputedly, when at the UN in New York, rented a flat from the tycoon.
He admitted he could not pose as “a champion of the people” but insisted his international career, including journalism and aid work, amounted to a “very un-elite life”.