I found this story on an episode of QI (series N, episode “New”).
The largest newspapers ever created were published between 1841-41.
They were known as “blanket sheets”, “mammoth newspapers” and “leviathan newspapers”, and were constructed out of a single sheet of paper in order to avoid paying a tax that charged publishers for the number of pages each newspaper had.
This tax was originally brought in to discourage people from buying papers that were critical of the government: the more it costs to make a paper, the more they charge the customer, and the less likely a customer is to buy one, slowly driving the papers out of business. This tax ran in Britain from 1712 to 1855, with the loophole to the tax issue coming with the advent of the cylinder printing press, which allowed such huge news sheets to be printed.
The tax was eventually abolished, which led to much more affordable papers, and papers that could directly target poorer demographics. Before this point, you had ‘penny sheets’, which weren’t strictly news (often they included a lot of smutty fiction), but managed to integrate enough news for the poor to know what was going on.