Ask a primary teacher where the week goes and lesson planning will come up fast. Slides, worksheets and quizzes for a single class can swallow hours before a lesson ever starts, and that time usually comes out of evenings and weekends.
The clever bit
Aila is Oak National Academy's AI lesson assistant, built to help teachers put together lesson plans and teaching materials that they can then check and edit. In an evaluation commissioned by the Education Endowment Foundation, researchers at NFER randomly encouraged some teachers in 106 English schools to use it for ten weeks in autumn 2025.
Teachers kept diaries of their prep time for one class. Among the 416 teachers analyzed out of 464 randomized, those encouraged to use Aila reported weekly preparation falling from about 3.32 hours to 2.51 hours, a saving of roughly 49 minutes. Independent reviewers rated the teaching materials no worse than those made the usual way. Planning time was measured for a single class each week, so the saving is per class, not across a teacher's whole timetable.
Hooray
Close to an hour a week handed back to a primary teacher is real time for marking, for a pupil who needs extra help, or simply for going home earlier. And it came without a drop in the quality of what landed in front of the class.
What comes next
Planning time was self-reported, and about 10% of teachers were left out because their diaries were incomplete. Teachers in both groups could use other AI tools. The trial ran ten weeks, didn't measure whether pupils learned more, and the reviewers' quality ratings agreed only moderately.