Environmental campaigners collected 40 sacks full of free newspapers from around London and brought them to City Hall on Wednesday night.
Project Freesheet aims to highlight the hidden environment costs of so-called free newspapers.
Volunteers from around the country collected discarded copies of Metro, thelondonpaper and London Lite from the streets, from public transport, from waste bins and from anywhere else they could find them.
In the evening all the papers found over a two-hour period were brought to City Hall for a photo opportunity.
Now they will be taken to Gillett Square in Hackney where artist Sumer Erek will build a house with the paper.
The campaigners had hoped to gather 10,000 papers but the final total was nearer 5,000.