However, in management buyouts, which account for the majority of private equity deals, jobs were cut in the first year, but grew by an average of 36 per cent over six years. Yet workers were £83.70 ($204) a year worse off than other private sector workers because wages grow more slowly.

Furthermore, some 40 per cent of managers in private equity firms said they are hostile to trade unions, while just one in 10 said they were positive about the role of unions.

“Private equity firms pride themselves on their ability to squeeze performance from the organisations they own, and they turn up the pressure on individuals in order to do so,” said Will Hutton, chief executive of The Work Foundation, which released the report.

The report also found that where an outside management team is introduced to an organisation in a management buy-in, employment falls on average by just under a fifth over a six-year period. Workers are on average £231 ($554) a year worse off than other private sector workers.

The report concluded that there was an urgent need to ensure private equity firms throw open their books to proper public scrutiny, that they pay appropriate levels of tax, and that the growth of private equity is not exposing economies to a risk of instability due to the levels of debt the industry takes on as it grows.