Charlie Hebdo cartoon: I knew I had to express defiance because I wanted to be true to the spirit of the magazine

The Independent's cartoonist on his globally admired response to the Paris atrocity

The cartoon produced by The Independent's Dave Brown following the Charlie Hebdo massacre

As a cartoonist, I often have to come up with a take on unpleasant events, but I don’t think I’ve ever been confronted with anything quite like the murders at Charlie Hebdo – people being killed for doing exactly the job that I do.

Generally I’m thinking, “How do I make something funny?”. But when something horrific like this happens, a belly laugh isn’t what you're looking for. Tragic stories can be quite difficult. So you have to analyse what exactly your response is and what you want to say.

I wanted my response to be true to the spirit of Charlie Hebdo. I knew they’d want the magazine to carry on, so it had to be a gesture of defiance. So I thought: I've literally got to draw a gesture. Hence the hand rising out of the newspaper. Originally I drew it for my usual slot on page three, but then it became the front page of today’s Independent, and I think that really made it stand out.

Drawing it was quite an emotional experience. If I had known any of the Charlie Hebdo team personally it would have been even harder. But what drives you as a cartoonist is being angry at events, and being angry with things you see as ridiculous, wrong-headed, venal, evil.

I think the cartoonists at Charlie Hebdo would have understood what I drew. Compared to the quite realistically drawn newspaper, I tried to make the hand as cartoony as possible. The yellow colouration of the hand is a particular reference to the work of Charb, Charlie’s editor-in-chief Stephane Charbonnier, whose figures were always yellow. So that was a little homage to him, the cartoonists, and the magazine as a whole.

I hesitate to call satire a weapon, but it is definitely a thing these people detest. They don't have a rational argument, and responding to something as immediate as visual satire is beyond them. It has a power which they can't match, so their only answer is to close it down by whatever means. And that's always been the case with fascists and extremists across the ages. Being mocked is too much for them to take. So we need to find a way carry on doing it and carry on laughing at them.

In the past I've had death threats because of cartoons I've done. Apart from the initial shock, I haven't been particularly worried by them, but there are always crazy people of all persuasion, religions and outlooks who don't like what you do. And that is the job: it's about challenging ideas, and that's bound to upset people.

Having said that, I don't feel particularly brave as a cartoonist. I do what I do. But the guys at Charlie Hebdo were certainly brave. They knew the threats they faced were very real.

Some people are now calling for newspapers to print depictions of Mohammed, but in this case it's not really the subject. It wasn't Islam, or Muslims in general, who carried out this atrocity. It was a small group of madmen. We have to point out their insanity. You've got to see who the real culprit is, and target them, and resist taking this rather more scattershot approach. There's nothing wrong with offending people, but in this case it's not the religion that we should be mocking. It's a particular strand of a criminal, barbaric, medieval mindset that has access to modern weaponry.

I was saying to someone recently that we're privileged to live in a country where cartoonists don't get locked up, or worse murdered, for what they draw. But of course it shouldn't be a privilege, it should be a fundamental right. There are still plenty of countries, and not just Islamic ones, where cartoonists are getting imprisoned for caricaturing their leaders. So it's a fundamental right that we need to keep reasserting.

There are times when I have disagreed with things Charlie Hebdo’s done and said, but that's the whole point of free speech - we can have those arguments. They get to draw what they think, I get to draw what I think, and we can all argue about it afterwards. And we need that discussion to go on. Whether it's visual or verbal, we need that give and take of ideas.