The word “indecent” is inherently vague and in consequence nobody can say with any certainty what is illegal. The consequences of a conviction are very severe so the lack of clarity has the effect of making illegal a much wider range of photographs than Parliament intended.
Replacing the word "indecent" with the word "pornographic" clarifies what is illegal, sets the boundary where most people currently believe it to be, reduces the harm caused and does not reduce the protection to children.
There is nothing inherently indecent about children but an atmosphere has been created in which it is unsafe to take pictures of any children apart from your own, and then only with some caution. If the law assumes that children are inherently pornographic then it encourages the belief that they are inherently pornographic.
The poorly defined law also leads to injustice. If a crime known as child pornography encompasses a wide range of photographs that are not pornographic then people can not be expected to know what the law is. This problem is exacerbated by the lack of transparency. The public are not allowed to see the photographs which result in conviction.