An assembly on Easter and Christianity at Oldknow Academy in Small Heath had been put on "especially" for the benefit of Education Funding Agency inspectors, a report has said.
The findings will make clear that staff told inspectors "they had been instructed to add Christianity to learning because of our visit".
A timetabled literacy lesson at the school was also switched for a religious education lesson on Christianity, according to the report.
Michael Gove's assertion that new rules could force schools to actively promote "British values" has sent the Twittersphere into a frenzy.
Five schools investigated in the wake of "Trojan Horse" claims will be put in special measures, while a sixth with remain under sanctions.