Three managers at private cleaning firm ISS have been arrested on suspicion of blackmailing migrant workers.
The managers were arrested during a raid at Kingston NHS hospital in south west London on Thursday of last week.
The three had allegedly told undocumented migrant workers working as cleaners at the site that they would report them to the immigration authorities.
There are allegations that managers were “skimming” money from the workers.
The raid went ahead after a tip-off from the Kingston Race and Equalities Council.
The company, ISS Mediclean, employs 43,000 workers at NHS and private hospitals across Britain.