Over 76% of supply teachers are employed through supply agencies rather than schools. They are denied the right to contribute to and access the Teacher's Pension Scheme. Agencies must be made to pay the Employer's contribution and give supply teachers the same pension rights as other teachers.
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The daily charge to schools by an agency for a teacher can be as much as £100 more than the amount paid to that teacher. Agencies should use this money to pay Employers contributions.
There is a steady increase in the casual employment of teachers to fill recruitment and retention gaps.
https://www.teachers.org.uk/edufacts/supplyteachers
https://www.educationsupportpartnership.org.uk/blogs/claire-renn/handling-money-difficulties-supply-teacher
https://www.bbc.co.uk/news/education-35911015