London, UK. June 29th, 2016. Petros Elia, General Secretary of the United Voices of the World union speaks at the rally on the 22nd day of the strike by cleaners employed by anti-union cleaning contractor Thames Cleaning at 100 Wood St. Credit: Peter Marshall/Alamy Live News

- Image ID: G6BJ57

London, UK. June 29th, 2016. Petros Elia, General Secretary of the United Voices of the World union speaks at the rally on the 22nd day of the strike by cleaners employed by anti-union cleaning contractor Thames Cleaning at 100 Wood St. Credit: Peter Marshall/Alamy Live News

Peter Marshall / Alamy Stock Photo

Image ID: G6BJ57