What does Ofsted say about fidelity?

In their guidance Choosing a phonics programme, Ofsted says that schools should take an approach to phonics ‘that is rigorous, systematic and used with fidelity (any resources used should exactly match the Grapheme Phoneme Correspondence (GPC) progression of their chosen SSP approach), and that achieves strong results for all pupils, including the most disadvantaged.’ (Ofsted, 2023)