For British colonialists, the fertile and cool uplands of central Kenya were the “White Highlands”, to be reserved exclusively for European settlers. Local communities were forced from the land, which was turned into plantations for tea and other crops.

In recent decades, descendants of the displaced have fought to reclaim their ancestral land, some of which is now occupied by multinational tea companies and other large corporations.

The fight for restitution is the subject of Kikuyu Land, a documentary film directed by the Kenyan film-maker Bea Wangondu and her American counterpart Andrew H Brown that is being released in the UK on Friday.

“Colonial structures didn’t just shape land and labour in Kenya. They created patterns of power that thrive today globally,” said Brown. “This isn’t just a Kenyan story. This could be told sadly in almost every part of the world.”

In 1902, under Sir Charles Eliot, then commissioner of the East Africa Protectorate (present-day Kenya), a law was passed making vast tracts of fertile ancestral land “Crown land”, allowing the government to sell and lease land to white settlers to encourage their settlement and farming, ignoring African communal land ownership systems.

The policy attracted settlers and led to the violent displacement of local communities to marginalised, crowded and less-productive “native reserves”.

In 1962, a year before independence, the colonial administration initiated a redistribution programme to transfer farms in the highlands from departing white settlers to landless Kenyans. The programme was aimed at purchasing land in the highlands from willing white settlers and reselling it to Kenyans on credit.

By the time it ended in 1971, about 1.15m acres of land had been bought from 780 white farmers and sold to approximately 35,000 Kenyan families. But much of the land remained with the political elite and foreign corporate interests, including companies that held huge plantations.

The idea of the film was inspired by Wangondu’s curiosity since childhood about why her grandfather had disproportionately vast land, compared with his neighbours. With answers unforthcoming from her family, she decided to dig deep into colonial history.

Having worked for international film companies and news organisations for years, Wangondu wanted to tell her own story, asking questions that have shaped her perception of herself and her family. “It’s time for us to tell our stories in our own voices and in our own understanding,” she said.

She discussed the idea with Brown in 2021 after they met while working on a National Geographic production, and they pursued it.

Kikuyu Land follows Wangondu’s search for answers about her family’s land, interspersed with a wider investigation into tea plantations and the story of the pursuit by one man, Mungai, to reclaim his family’s ancestral land.

“They raped our country, they displaced us, they took our land and they did the unfairness they did to us,” Mungai tells Wangondu in the film.

Wangondu and Mungai’s journeys in the documentary expose colonial legacies, buried histories and family pains that the two struggle to face up to. In one scene, Mungai crouches under a tree and grieves after his aunt shows him a spot, now inside the fence of the tea farm whose land his family is claiming, where their patriarch was buried.

Kenya was under British rule from 1895 to 1963, first as a protectorate then as a colony. The period was characterised by racial discrimination, forced displacement and labour, and brutal suppression of resistance.

Members of the Kipsigis and Talai communities have made calls for redress in recent years over the violent eviction of their ancestors from their lands in the Rift Valley to make way for tea plantations owned by white settlers. In 2021, UN special rapporteurs expressed concern about the British government’s failure to provide “effective remedies and reparations” to the two communities.

Kikuyu Land premiered at the Sundance film festival in the US in January and had its UK festival premiere in June at the Sheffield DocFest. It will screen at the NBO film festival in Nairobi in October.

Joseph Njenga, one of its producers, said hearing stories while making the film of people who suffered pain and atrocities caused by the colonial administration had left an emotional imprint.

“My head could not contextualise and process the pain that was brought upon us – and for no reason,” he said.

• Kikuyu Land is in UK cinemas from 2 October