glorygloryeze
Tom Huddlestone
I would suggest that you are then breaking the law. The agency workers directive came in about 2 years ago.
https://www.gov.uk/agency-workers-your-rights/overview
How are they breaking the law? That rule says that after 12 weeks the employee is entitled to the same rights and qualify for equal treatment.
That's not the same as having to offer them a 'permanent contract'. For example they are entitled to sick pay and paid holidays, but they are NOT entitled to redundancy pay or to claim for unfair dismissal like permanent employees would be.