In one scene shot on 19 March, two distributors, with their branded jackets removed, are captured boarding a number 56 bus in Barbican, each with two full bundles of newspapers.
They get off the bus four stops later and put the papers into recycling bins, removing the strapping ties. They get back on a bus in the opposite direction and return half an hour later with two more bundles each, which they dispose of in the same way.
In further footage taken on 23 March, two distributors are seen taking trolley-loads of papers into an alley near Liverpool Street Station and placing them in recycling bins. They stop binning the papers temporarily when two passers by walk through the alley.
Further dumping was captured on 3 April in the area around St Paul's.
In each case, the distributors remove or conceal their jackets before discarding the copies.
Phillip Swinburne, director of security specialist Swinburne Associates, a former police officer who was previously specialist policy adviser to the National Hi-Tech Crime Unit, observed the incidents and compiled a dossier of evidence.
Steve Auckland, managing director of Metro and London Lite, said: "Our investigation shows a repeating pattern of dumping by thelondonpaper vendors at different locations in central London. They are desperate and oversupplying the market. At London Lite we try to keep waste to a minimum. That's why we distribute 400,000 copies."
NI defended its distributors, who are paid by the hour rather than per copy.
A spokesman said: "We have no desire to get involved in any dirty tricks campaign. However, if there is any evidence of this, the matter will be investigated and dealt with immediately in the appropriate manner."
Last week, Westminster Council threatened to ban both free titles from its streets unless the publishers footed a £500,000 bill for recycling over the next two years.
In February, NI raised distribution of thelondonpaper from around 400,000 copies to around 500,000 copies a day.