This included the NHS, where only 7% of very senior managers and 11% of senior managers were of an ethnic minority background despite making up 18% of the non-medical workforce.
Discrepancies in the employment rate were also present as figures showed white people were more likely to be employed than ethnic minorities across the nation.
Released alongside the launch of the ‘Ethnic Facts and Figures’ website, May promised the audit would reveal “uncomfortable truths” about society.
“If these disparities cannot be explained then they must be changed,” she said.
Race Equality director of business in the community Sandra Kerr OBE called the audit a “bold step” that would “enable a better understanding” of the difficulties surrounding race equality.
“I would strongly encourage all employers to take steps to address race inequality within their organisation,” she added.
David Isaac, chair of the Equality Human Rights Commission (EHRC), praised the prime minister for releasing the data but said the results were not shocking.
“Only by taking focused action to tackle race inequality, can Britain become a fair country in which individuals can reach their potential and our communities can live and work together to create a strong and a cohesive society,” he said.