https://www.theguardian.com/commentisfree/2016/jul/15/brexit...
Besides, there's no boundary between "media" and "politicians"; early on while he was PM Johnson was paid more to be a Telegraph columnist than his official PM salary.
The report is based on analysis of two days of press coverage each week for London editions of nine national newspapers over 4 months of the campaign. Of the 2,378 articles analysed which were focused on the referendum, 41% were pro leave as against 27% pro-remain.
The original site is no longer maintained and redirects to the new wayback machine, but that site is down, sadly. So here's a snapshot from the old wayback url.
Fake news about the EU was so prevalent that the EU started maintaining its own list. Note that one of the "journalists" that wrote these fake news stories was Boris Johnson himself.
"Media was quite anti-brexit" not really. Unless you really think the GDPR prevents kids from writing letters to Santa Claus