Full marks to Oxford residents, who have responded with great gusto to the city council's invitation to send in mobile phone pictures of graffiti.

We can't say it is a pleasure to be devoting our front page, as well as two inside pages, to this subject.

But our coverage shows the extent of the problem.

Now the task is to fit the tags to the perpetrators - and that, of course, will be much more difficult than taking pictures of the images.

Graffiti criminals - we decline to call them artists - are devious characters who set to work when no-one is about and they have little risk of being caught.

But there must be plenty of tell-tale signs lurking inside or outside their homes.

Discarded aerosol cans, paint on hands and clothes - many of us will have suspicions about the people who are disfiguring our city.

We hope that anyone with information will contact the police and council so that they can be taken to court.

Meanwhile, congratulations to the council for its initiative and to council taxpayers who have responded so well.

Council staff can now get to work to clean up our streets and buildings.