Besides Boris Johnson - an important and charismatic actor as a no-nonsense figurehead for Leave - their campaign has displayed limited star power. Especially, since they seem to be attracting some choice overseas supporters of Brexit including French National Front chairwoman Marine Le Pen and Donald Trump.
To maximise effectiveness, brands need to adapt to reduced attention spans. There are two tactics. Either, seek out the rare moments when consumers are forced to concentrate deeply, the cinema being a prime example, or accept that consumers will only be paying partial attention and brutally simplify the copy. Make it shorter and simpler. Brands that adapt will be at an advantage compared to those who don't.