The head teacher warned parents

[Bassim]

I am wondering if my sentences are grammatically correct. I believe that the last part of my sentence is not grammatically correct, but unfortunately I could not remember any better phrase.

The head teacher warned parents that the school would not allow parents to take their children on holidays outside of the regular holiday season.

 

[GoesStation]

It's grammatically correct. In my country, such a policy would have dubious enforceability.

 

[emsr2d2]

In the UK, parents can be fined for taking their children out of school during regular term time. It is regularly enforced although there was recently a court case because a parent appealed against the fine and the judge decided that because the trip the child went on could be deemed "educational", the fine should be cancelled.

 

[Tdol]

I would use on holiday, though holidays is OK.

 

[Rover_KE]

I'd change the second 'parents' to 'them'.