If digital material which requires an imprint is published without one, then both:
the promoter of the material
anyone else on whose behalf the material is published
may commit an offence.
Whether it is the police or the Electoral Commission that is initially responsible depends on the purpose of the material in question, rather than who has published it.
The police will enforce material which relates to:
a particular candidate
a particular future candidate
The Electoral Commission will enforce material which relates to:
political parties
categories of parties, candidates and/or future candidates including categories based on:
their support for or against particular policies
their holding particular opinions
any other reason
Where there is uncertainty in a particular case as to which body is responsible for enforcement, this will be resolved between the enforcement bodies on a case by case basis.
The Electoral Commission will regulate digital imprints in line with our enforcement policy.