PLAID Cymru have been told to remove on-street advertisements in Cardiff after failing to ask the council for permission.

The party used "clean graffiti’’ on pavements in the capital at the weekend - aiming to get their message across to around 250,000 people in town for the Wales v Ireland rugby match.

The marketing tactic sees power washers used to "write’’ messages into stonework.

Plaid used a stencil to display its logo and election slogan in a number of locations around the Millennium Stadium, as well as bus and train stations.

But Cardiff Council confirmed it had received a number of complaints about the issue and has now told Plaid it must clean up the "clean graffiti’’ - or face a fine.

A spokeswoman said: "The council has been made aware of a number of instances of unauthorised advertising stencils on the highway in the city centre.

"Written permission was not granted, and the council has not authorised this practice.

"The immediate removal of the stencils has been requested at the cost of those involved.’’