For the purposes of this Act, a video recording contains a video work if it contains information by the use of which the whole or a part of the work may be produced; but where a video work includes any extract from another video work, that extract is not to be regarded for the purposes of this subsection as a part of that other work.

Where any alteration is made to a video work in respect of which a classification certificate has been issued, the classification certificate is not to be treated for the purposes of this Act as issued in respect of the altered work.

In this subsection, " alteration " includes addition.