Should people who use illegal drugs be able to have them checked before taking them?

Should people who use illegal drugs be able to have them checked before taking them? Testing in nightclubs happens in some countries around the world. Commentators have suggested that criminalisation is clearly ineffective when it comes to stopping kids using drugs while allowing them to use an unchecked toxic substance is an unjust punishment for experimenting. Is it a step too far? Stephen got the views of commentators Emma Woolf and Simon Warr.