Workers for SCA Logistics at the Port of Tilbury, Essex, struck for two days last week against plans to bring in zero hours contracts.
The dockers are members of the Unite union. They fear the permanent workforce of 24 could be replaced by agency staff on lower pay and worse conditions.
This could also undermine safety in an industry where accidents can have devastating consequences.
Jane Jeffery is a regional officer for Unite. She said the contracts would “be turning the clock back 50 years to when you had to rely on the tap on the shoulder to see if you had work”.