Dr Julian Lewis: There is a vast difference between stigmatising individuals who are at risk, which is not proposed, and stigmatising a barbaric ideology, because the idea is to save individuals from being sucked into the ideology.

Caroline Lucas: I think that I thank the hon. Gentleman for that. There are problems with the way he describes things in a black and white way. Of course I would be the first to say that we are seeing barbaric acts, which are part of a barbaric ideology. But to continue to use that language is not helpful when we are talking about young people. There are young people who have got mixed up in this in an ignorant way. I am not trying to excuse what they have done; I am just trying to understand it. If we think in terms of barbaric ideologies, then that suggests someone who has spent an awful lot of time becoming involved in this, understanding it, knowing it and thinking of themselves as ideologues rather than as people who may have mental health problems, who may be excluded, who have faced massive racism in their lives and who have ended up in a very unfortunate position for a huge number of reasons that are not necessarily helpfully described when we talk about a barbaric ideology.

Dr Lewis: The hon. Lady is very kind. This will be my last intervention, so she has an open goal after that. I simply say that nobody hesitates to describe Nazi ideology and communist ideology in terms of their barbaric nature. If we are to succeed in saving people from being drawn into this form of barbarism, we have to get it into the same category, because, fundamentally, it comes from the same drawer of ideologies.

[For Julian's speech in this debate click here.]