Guardian readers waking up the day after the Brexit vote received an email from Kath Viner, Editor of The Guardian. She warned that:

“These are perilous times for progressive politics — and at moments like these the world needs the Guardian more than ever.”

The message was part of a recruitment drive for its membership scheme, which the paper hopes will help staunch its financial wounds without necessitating the introduction of a paywall. The scheme offers some added-value content and benefits, but the main benefit for members is the knowledge that they are supporting a voice that shares their values.

Viner’s plea worked. Membership numbers swelled that day and for days afterwards, as its primarily progressive readership found itself outnumbered in the referendum. Membership may yet play an important part in bridging the gap left by declining print revenues and the damage done to its digital revenues by ad blockers.

Other media brands are also turning to voluntary mechanisms to boost disappointing digital advertising revenues. For thousands of influential YouTubers, fan patronage platform Patreon is now a source of revenuethat compares with Google ad sales, while online brands like The Young Turks rely heavily on membership schemes similar to the Guardian’s.

Patronage has always played an important part in supporting journalism, but greater reliance on donations will increase media bias at a time when public debate has become dangerously polarised.

This is because payments and donations encourage very different behaviours by media brands:

A paid subscription model has to deliver interesting content — and while that often means indulging its readers, it also gives news providers licence to be provocative and challenging. On the other hand, a model based on patronage has continually to demonstrate to donors that it is promoting supporters’ preferred agenda — relentlessly pursuing certain narratives and arguments to the exclusion of others and using opinion pieces to virtue signal.

There are lots of problems with the economics of news — from subsidy by the superrich to clickbait ad models and a journalist brain drain — and truly balanced news coverage may be a chimera, but media brands funded by patronage risk becoming mere pressure groups — just as campaigning organisations like Greenpeace and ONE are learning to act like media brands.

If news organisations can’t differentiate between journalism and propaganda, why should the public? And if the news media no longer functions as a trusted independent arbiter, politicians, businesses and other organisations will find it easier to ignore when it tries to hold them to account.