British child labor laws?

[Marty Larson]

So here's my question in regards to the filming of the HP movies - 
they (whoever they are - WB, Heyman, etc.) say that the filming takes 
so long because under the child labor laws of Britian, The kids may 
only film for 4 1/2 hours a day.  No problem with that, but at what 
age are they no longer considered under these regulations?  The 
research I did said that the age requirement is related to compulsary 
school age.  So what is that in Britain?  If it is say, 16, then this 
shouldn't be a critical a factor for OotP, correct? And the remaining 
three movies can move along guite a bit faster. Or is it older?  When 
do you reach your majority in Britain?

Marty