Frederik Van Zyl Slabbert: Politician and activist in the vanguard of the struggle against apartheid

Frederik Van Zyl Slabbert was one of the big beasts of apartheid-era politics, best-known for abandoning parliament in 1986 to liaise with the exiled African National Congress. He had burst on to the South African political scene 12 years earlier when he pulled off an upset in the all-white general election by winning the Cape constituency of Rondebosch for Helen Suzman's Progressive Party, beating a segregationist incumbent.

"Van", as he was called by friends, had only joined the Progressives after his nomination but immediately established himself as leader-in-waiting. This former provincial rugby forward certainly looked the part: tall, broad and handsome with a resonant baritone voice, he exuded the kind of rugged manliness that played well in white South Africa, and his credentials were certainly impressive – an Afrikaner university professor who had sailed through his cum laude academic career.

My first contact with him came three years later, when, as a 17-year-old, I campaigned for his party, by then called the Progressive Federal Party (PFP). He impressed me hugely as a magnetic figure who combined pragmatic intellectualism with earthy machismo. His leadership helped to transform the PFP from a fringe collective of English-speaking liberals to the official opposition.

Slabbert's early years had their share of heartache. His parents divorced when he was three, leaving him and his twin sister to live with their mother in Pretoria, and then, at seven, with their uncle in Johannesburg, and finally with their grandparents on a farm in Pietersburg. Yet despite this chaos he seemed to excel at everything he touched: head boy, captain of the rugby and cricket teams, top student. He dreamt of becoming a minister in the segregationist Dutch Reformed Church and went off to study at theology, sociology and Afrikaans at Stellenbosch University.

Exposure to alternative intellectual traditions, and to black churchgoers, prompted a shift leftwards, although this liberalism should not be overstated. The Progressive Party he embraced had the dubious policy of supporting a "qualified franchise" for blacks. Slabbert, who became leader in 1978, later steered it towards supporting a universal franchise within a federal system.

Their rather naïve aim was to win enough seats to secure a future power-broking role. However, the military-dominated regime of P.W. Botha had ideas becoming a nuclear power that used its security and intelligence services to bypass parliament and wipe out opposition. Assassinations, state-sponsored massacres and mass-scale detention without trial became the norm. On the other side was the sanctions campaign and armed struggle of the resurgent African National Congress, and, at home, the United Democratic Front (UDF), a network of trades unions and community organisations whose aim was to make the country ungovernable.

In this climate, the white parliamentary opposition looked increasingly insipid, although it took Slabbert a while to recognise this, and he made several quixotic errors along the way. He tried to broaden their electoral base by attacking the sanctions campaign and backing military conscription and requested a special meeting with Botha, meekly pleading for a change in course (Botha secretly recorded the meeting and embarrassed Slabbert by releasing the transcript). The final stage came in 1985 when Slabbert founded the National Convention Movement with Mangosuthu Buthelezi, whose Inkatha forces were being armed by the military. The result was that this movement was still-born, forcing Slabbert to reconsider.

Later that year he met with the ANC in Lusaka and in February 1986 resigned as leader of the opposition and as an MP, saying that he "refused to be in the slipstream of the government's repression and incompetence". Suzman accused him of a "betrayal"; others said he lacked "balls", to which he responded: "The trouble with this country is that you have too many politicians with balls but no brains."

Slabbert and his friend, Dr Alex Boraine, who had joined him in abandoning parliament, established the Institute of Democratic Alternatives in South Africa, which played a significant role in bringing white opinion-makers into contact with the leadership of the ANC and UDF. Hundreds of white businessmen, editors, academics, politicians and military figures were in touch with the exile-based movement in the late-1980s, easing the way towards negotiations.

It was during this period that I got to know Slabbert, regularly joining him in his meetings and conferences. By then he was in his late 40s and his magnetism had given away to a quieter gravitas. My impression was that he was always intellectually and politically curious – and open to new ideas – while remaining inscrutable in his dealing with power brokers. He showed enormous patience and humility in frequently tedious meetings with young radicals, and soon established himself as a trusted facilitator who was particularly close to the future South African president Thabo Mbeki.

Slabbert recognised that this role had come to an end after the 1994 elections and he withdrew from high-profile politics, concentrating instead on business, academic and charitable interests, including George Soros's Open Society Foundation. Last year he left his post as chancellor of Stellenbosch University following a heart attack.

Frederik Van Zyl Slabbert, politician, academic and businessman: born Pretoria, South Africa 2 March 1940; married firstly Mana Jordaan (marriage dissolved); one son, one daughter), secondly Jane Stephens; died Johannesburg 14 May 2010.