Under the Copyright, Designs and Patents Act 1988 (CDPA), for copyright to subsist in a work, that work must be original. However, courts have not adopted a literal reading of this requirement. For over a hundred years, English courts have held that a significant expenditure of labour is sufficient. The consequence of this is that if A makes a work in which copyright subsists, and B subsequently adds his skill, judgement and labour, altering the form of A's work, B will potentially have a copyright in the work he produces. This suggests that copyright is not about protecting ideas, because one can acquire a copyright by expending skill, labour, and judgement, but no creativity or inventiveness.