The illegal detention and deportation of Caribbean immigrants by British authorities was the result of decades of racist immigration laws aimed at reducing the country’s non-white population, according to the report of an official inquiry that remained unpublished for years.

Revelations of the mistreatment of thousands of people from the Caribbean, the so-called “Windras Scandal”, have rocked the government of former British Prime Minister Theresa May, who led the drive to curb irregular immigration when she was home secretary.

Hundreds of thousands of Caribbean immigrants arrived in the UK between 1948 and 1971 on ships such as the Empire Windrush to fill labor shortages in the years after World War II.

In 2018, Britain apologized for its treatment of the “Windrush generation” after a crackdown on immigration meant thousands of people were denied basic rights despite having lived in Britain for decades. Several dozen were unjustly deported.

The previous Conservative government in 2022 refused to release the report, titled “The historical roots of the Windrush scandal”, refusing requests made under the Freedom of Information Act.

The report, now released by the Labor government, concluded that between 1950-1981 “every bit” of immigration or citizenship legislation was designed, at least in part, to reduce the number of black people who would be allowed to live and work in Britain.

“Significant immigration laws in 1962, 1968 and 1971 were designed to reduce the proportion of people living in the UK who are not white,” the report said, calling the Windras scandal “deep-rooted racism”.

This research was requested by the Ministry of the Interior itself and is based on hundreds of documents from the National Archives of the country, oral interviews and hundreds of discussions with ministry employees.

The report does not make any proposals to address the problem. But it finds that the lives of blacks and other people from minority backgrounds were “profoundly affected” by the policies of the British Empire.

In 2018 London said it would compensate some Caribbean migrants affected by the scandal.

“Gradually, race and immigration politics became intertwined (…) Even after slavery was finally abolished in 1833, the belief that blacks were either not entitled or incapable of equal status with whites in the British Empire remained intact”, the report concludes.