Graffiti vandals are causing tens of thousands of pounds of damage by "tagging" buildings and landmarks in Oxford - and police are appealing for public help to identify the main culprits.

Pc Paul Phillips with one of the tags

Four of the worst offenders call themselves Fresh, Pure, Bane and Epoch. Their signatures can be seen blighting areas across the city.

Oxford City Council spends about £30,000 a year cleaning graffiti from walls, plus the cost of employee time. However, it can scrub graffiti only from public buildings. The council's cleansing department has to be given permission to remove it from non-council property by the landowner.

The council has spent up to £3,000 in the past few months just removing the tag "Pure".

Pc Paul Phillips, of Oxford police's city centre unit, said most tags were concentrated in the city centre, Headington and Jericho areas.

He emphasised tagging was a serious offence and police were keen to catch taggers red-handed.

He said: "It is criminal damage and if people see it happening they should call the police straight away on 999."

He said railway bridges and the roof of the Oxford Ice Rink in Oxpens Road were places where graffiti had been daubed, although the ice rink had now been cleaned up. "People involved in graffiti-writing are putting themselves in obvious danger by operating at those locations," he added.

Pc Phillips called on anyone who knew the identity of the graffiti writers, or had seen the same tags on school or college folders or exercise books, to get in touch with police.

Malcolm Hart, of the city council's cleansing department, said: "It's a terribly frustrating problem. We dedicate so much in time and resources to removing graffiti.

"We need to remind people that graffiti is a criminal offence and must be reported to the police.

"The council works very close with them, and is building up a data base to identify graffiti hot spots and to use in evidence in prosecutions."

Bill McCardle, chief executive of the Oxford city centre management company 0X1, welcomed the initiative to clamp down on taggers.

He said: "It will make people feel more proud of the city, make them feel safer and make Oxford feel a friendlier place to visit.

"It is right at the top of the priorities for OX1 to make Oxford a much cleaner city."

Carfax city councillor Paul Sargent said: "A lot of these tags are ubiquitous. Old buildings, homes and businesses are ruined by mindless vandals. Perhaps we need to have a place were people can spray graffiti, for example graffiti walls near skate parks."

Anyone who knows the identity of the those responsible for the four tags should call Pc Paul Phillips via the police inquiry centre on 08458 505505, or the free anonymous Crimestoppers number 0800 555111.