Many Guarani have no option but to work as wage labourers on the vast sugar cane plantations and cattle ranches, forced to scratch out a living in a society created on their own land without their consent.
We marshalled supporters at the Brazilian embassy in London for a vocal show of support for the Guarani, broadcast live over social media (see video below).
There were further protests in São Paulo, San Francisco, Berlin, Madrid, Barcelona and Milan. We also handed letters of protest from Survival and the Guarani people themselves, in to representatives of Brazil's government.
Ladio stood defiant in a tribal headdress and face paint. Though London on an April morning was rather colder than what he was used to in central Brazil, he nevertheless spoke passionately - both to the supporters who were there to see him, and to the embassy official who received his letter.
As the son of the murdered tribal leader Marcos Veron, Ladio has an understandable emotional investment in his people's struggle. All of the Guarani feel a profound stake in it. The theft of their ancestral land by ranchers and agribusiness has been a trauma endured over decades.
They face violent harassment by gunmen when they try to reoccupy tiny patches of the land, most of which has been deforested and turned into plantations. Their water is polluted with pesticides, and they are partitioned off from the land by wire fencing. Some communities are living in makeshift camps on roadsides.
Paper laws, paper promises
The fact that the Guarani have to risk their very lives for their land is both tragic and baffling. It is rightfully theirs under both Brazilian and international law.
The fact that cases are on the books over Guarani land tenure in both Mato Grosso do Sul state, and the federal capital of Brasilia, is a tacit admission from the Brazilian establishment that the tribe at least has a claim.
It's their land, yet they have been trapped in legal hell for decades, waiting for full demarcation and the proper enforcement of their rights.
Mato Grosso do Sul itself is so dominated by agribusiness that it is almost impossible for the Guarani to appeal to politicians and other authorities there, as they are emphatically on the side of the ranchers. Men like Jose Teixiera serve as state deputies while owning large ranches, and happily partner with big corporations profiting from sugarcane produced on Guarani land.
This footage from 2016 shows heavily-armed Brazilian police evicting a small group of Guarani from their land. The tribespeople are unarmed, they are peaceful - they make their case in strong words but present no threat whatsoever. Yet around 100 men were sent to clear them off a scrap of land so that their village could be bulldozed.
Exploited, low wage labourers on their own land
Incidents such as this clearly illustrate the situation. The Guarani have very few allies in Brazil - certainly not among the country's rulers. They are forced to look elsewhere to bring global attention to their plight, and to exert pressure on the people who have the authority to transform their situation.
Survival International has been campaigning in partnership with the Guarani for over 30 years. The Guarani are the most populous indigenous people of this part of central Brazil, and they are slowly being destroyed.
In pursuit of profit, the over-mighty ruralista lobby has subjected them to poverty, violence, disease and destitution. Some live and work in towns and cities in Mato Grosso do Sul state, or further afield. Many more have no option but to work as wage laborers on the vast sugar cane plantations and cattle ranches, forced to scratch out a living in a society created on their own land without their consent which offers them next to nothing.
According to some studies, the tribe suffers the highest suicide rate in the world, a problem which is especially acute among younger people.
With international pressure, the Guarani can assert their legal rights
There is hope, however. International pressure has been proven to be effective in holding Brazil's leaders to account and empowering indigenous people through recognition of their land rights.
In 1992 for example, after years of campaigning, the government relented and agreed to create the largest forested indigenous territory in the world: the Yanomami indigenous territory in the northern Amazon. It is an area the size of Switzerland that is now home to over 20,000 tribal people.
In 2014, concerted campaigning by Survival supporters pushed Brazilian authorities to carry out an unprecedented crackdown on illegal logging, drastically improving the situation facing the Awá people from the Amazon's eastern fringe.
And last year, similar pressure pushed the Minister of Justice to sign a decree creating a protected territory for the hard-pressed Kawahiva people, a small uncontacted tribe and one of the most vulnerable peoples on the planet.
We're devoted to giving tribal peoples a platform to speak to the world. As Ladio himself said: "We will resist at any price. All we have left to lose is our lives."
His powerful speech at the Brazilian embassy, and the sight of him moved to tears as he addressed an embassy official were heartening for everyone who turned out in solidarity with his people.
More importantly, this sort of direct action could help to tip the balance in the Guarani's favor. There is always hope.
Lewis Evans is an author and a campaigner at Survival International, the global movement for tribal peoples' rights.