" … Buthelezi leaves for London tomorrow [Tuesday] to attend the funeral of his late friend … with whom he stayed in very close contact, even after her retirement from politics," the Inkatha Freedom Party (IFP) said in a statement on Monday.
"They found themselves to be kindred spirits, equally committed to the cause of freedom in the world, and to a non-communist outcome to the South African liberation."
Thatcher, Britain's only woman prime minister, died of a stroke last week, at the age of 87. She led the Conservatives to three election victories, governing from 1979 to 1990, the longest continuous period in office by a UK premier since the early 19th century.
"Like Buthelezi, Thatcher stood by her principles and recognised that the abdication of principles only leads to decay," the IFP said.
"She shared Buthelezi's dream to make South Africa great … She loved South Africa and saw and hoped for a leadership place in the world for our country."
Buthelezi would be accompanied by his adviser, IFP Member of Parliament Mario Oriani-Ambrosini.
Reactions to Thatcher's death
Britain Prime Minister David Cameron said on April 8 it was with great sadness he had learnt of the death of Thatcher. "We have lost a great leader, a great prime minister and a great Briton," Cameron said. Cameron cut short a trip to several European countries after the announcement, a spokesperson for his Number 10 Downing Street office said.
Britain's former leader supported the apartheid government when it was at its deadliest, killing many in the late 1980s in state terrorism at home and abroad in bombings and cross-border raids on neighbouring states accused of harbouring guerrilla fighters, said Pallo Jordan, a former Cabinet minister and stalwart of the ANC, on April 9.
"I say good riddance," he said on Talk Radio 702 last week.
Thatcher branded former president Nelson Mandela and his ANC movement "terrorist" amid concerns that they received backing from the former Soviet Union during the cold war era and because of their guerrilla war for democracy.
Jordan was at Mandela's first meeting with Thatcher after his release from 27 years in jail, at Downing Street in London in 1990.
Queen Elizabeth last week also expressed sadness and said she would be sending a private message of sympathy to the family. – Sapa