If you watch 'Hanging with Hector', the first thing you see is him spraying a wall. That's in the opening credits! This is what we're teaching people and this is what the national broadcaster thinks of as a good opening for a program. There's even a Playstation game which is about 'tagging' [graffiti slang for putting your name on a building]. I think that's the wrong sort of message to be sending.

We often get the argument that this is an art form and you have famous international artists like Banksy making an absolute fortune as a result of their graffiti-artist background. But if I want to see art I'll go to an art gallery. I don't want to be forced to look at it and have a visual assault on my senses every time I drive by. Nobody has the right to enforce their ideals or ideas of art on other people.

Frequently when people are arguing about allowing graffiti to happen they're talking about the kind of thing that someone like Banksy can do. But in reality we're often dealing with the kind of offensive and racist material that's not going to be shown in the Tate Modern . . . horrendous stuff that nobody would consider art. Would you really want this on your house? Think of the people who have to constantly go out and repaint their walls. It's costing them an arm and a leg and it's obviously going to have an affect on property values. The day I see some tagger gets caught, and see that the side of his house is covered with his own tag, that's the day I'll reconsider my opinions.

People often ask us to provide facilities for graffiti . . . places where people can tag legitimately. Now, I've been quoted as saying that it's going to happen but I can only make recommendations and it's not up to us to provide every facility that anyone could possibly want. It is up to us to provide a safe clean environment for all citizens.

Graffiti artists should put their own argument forward about whether facilities should be made available. If it is to be a legitimate art form then it has to legitimise itself and people have to take responsibility for that.

And they have to be responsible. Spraying graffiti can be very dangerous. We don't want to see someone killed because they've fallen onto train tracks or slipped off a building and impaled themselves on some railings. Recently two people were killed on a railway line in London and that could happen here.

The level of graffiti has increased, there's no doubt about it. Our department spent a half million last year. The Department of Justice has its own program for graf"ti on private and commercial property and they got a budget of three million. Unfortunately it's not our job to remove the graf"ti from private property, although many people contact us to ask us to do this. For this people should contact their area of"cers who will liaise with the Department of Justice. It's not our remit I'm afraid.

At the end of the day, I'm not an art critic. I don't decide what's good and bad. I decide what's legal and what's not legal, and if it's on one of our properties it's going to be removed. It doesn't matter how good it is. I'm not really concerned if the National Gallery decides that it's worth hundreds of millions of euro . . . it's still my job to remove it.

In conversation with Patrick Freyne