Zimbabwean tycoon John Bredenkamp has ridden political upheaval to become one of his country's richest international businessmen.

Over a four-decade career that has taken him from Harare's tobacco auction floors to Downing Street, he has shown himself an opportunist whose secretive business dealings have come under attack from the United Nations and non-governmental groups.

After flourishing under the white minority regime of Ian Smith, he later allied himself to President Robert Mugabe's post-independence government and built up substantial British assets.

Patrick Smith, editor of Africa Confidential, said: "On a continent where businessmen progress through a combination of hard-nosed pragmatism and personal networks, Bredenkamp is in the premier league."

Mr Bredenkamp's history has come under the spotlight after the emergence of documents showing he is a beneficiary of Kayswell Services, an offshore company paid at least £20m by BAE between 2003 and 2005.

Born in 1940, Mr Bredenkamp began his career at a tobacco auction house. By the late 1960s, he was captaining the Rhodesian rugby team and busting tobacco export sanctions imposed by the UN after the Smith government's unilateral declaration of independence from Britain in 1965.

He later expanded into oil procurement and dabbled in sports management. This took him to a Downing Street reception in the mid-1990s with John Major.

One of Mr Bredenkamp's most controversial business ventures was mining in the Democratic Republic of Congo. UN investigators concluded in 2002 that some of his business interests had illegally exploited mineral resources, although he denied the allegation.

His main business venture is Breco, an international private equity group that he set up after selling his Casalee tobacco company for $100m in 1993. He also has longstanding - if opaque - links with the arms industry in southern Africa, although he says he has always complied with weapons sanctions imposed against Zimbabwe by the European Union in 2002.