New rights for agency workers came into force last week.
The Agency Workers Directive gives them the same pay, holidays and hours as permanent staff after 12 weeks in the same role with the same hirer.
They will also get some maternity rights.
The Tories tried to wriggle out of the EU rule but failed.
The rule change is a small step forward. But the 12 week wait means bosses will bypass the rules by changing job descriptions or by firing and rehiring.
All workers should have equal rights from day one of their employment.