The school at the centre of a storm over a religious workshop was forced to abandon the trip for pupils at the eleventh hour after placard-waving protests which saw the police called.
Officers have been at Littleton Green Community School in Cannock every day since Friday because of parents' fury which sparked yesterday's demonstration at the school gates.
The 45-strong rally followed uproar last week when parents were warned their children would have a racial discrimination note recorded against them if they failed to attend the workshop.
Head of the Huntington primary school Lynn Small later apologised for her comments and withdrew the threat.
The trip to Staffordshire University for around 100 children to learn about Islam was due to have taken place yesterday.
But it was postponed by education chiefs over fears yesterday's lunchtime protest at the school in Colliers Way may get out of hand.
Police, who have kept watch outside the school each day since last Friday, moved the group on after an hour when pupils were due to leave for lunch.
Staffordshire Police spokeswoman Hazel Dockery said: "The 45 demonstrators were advised to keep noise to an absolute minimum to ensure the children's education wasn't disrupted."
The school and Mrs Small declined to comment on the latest developments in the saga today.
Ben Adams, Staffordshire County Council's cabinet member for learning and skills, said: "It is a shame the children had to miss out on the workshop."
It is planned to reschedule the trip for Littleton Green students at a later date.