Unwelcome Fly Posting on BT Street Cabinets?

BT Street Cabinet in Brook Street close to the
junction with Fort Street

A constituent has complained to me about the outbreak of advertising on BT's Street Cabinets. It would appear that at several locations in The Ferry, there are advertising posters stuck to BT's green Street Cabinets. 

At first glance, this does not appear to be the work of bill stickers, because the poster material displayed is advertising BT's Fibre broadband. I presume that it is BT itself that is responsible? 

My constuent finds this unwelcome and visually intrusive. I have written to BT to seek clarification about this. I have also contacted the planning department to check whether BT's planning consent includes permission to put up advertising material on their Street Cabinets.