Companies which plaster illegal flyposters across north London may soon find fewer people than expected turning up to their events.
"Cancelled" stickers will be put over fly posters in Islington
Stickers with the word "cancelled" will be put on flyposters in Islington, giving passers-by the impression the event has been called off.
The Transport for London (TfL) scheme began on Wednesday.
TfL have said that if the eight-week trial is successful, it could be extended to other parts of London.
Keith Ollier, from TfL, said: "We waste considerable time and money removing illegal fly posters every week.
"We all want our streets to look cleaner and smarter and this trial is aiming to do just that."
In neighbouring Camden, arts promoters have spoken out against flyposting bans.
Earlier this year, Hackney Empire's artistic director Roland Muldoon said the crackdown had gone too far.
He added: "Political flyposting will never be stopped, so all that will happen is that arts venues will suffer."