From the moment that the High Court ruled the Met Police's ban was unlawful, this was an obvious consequence.
Criminal charges have been dropped against climate change protesters who were arrested under a police order that was later ruled to be unlawful.
The Crown Prosecution Service (CPS) said 105 cases were being discontinued against Extinction Rebellion (XR) supporters who were detained during the action in October.
More than 1,800 people were arrested during the XR Autumn Uprising protest, which saw locations around central London, City Airport and the Tube network targeted.
Police initially made use of public order legislation, a section 14 order, to restrict the action to Trafalgar Square, and after repeated breaches went further, effectively banning XR protests from the capital.
High Court judges ruled that the effective ban was unlawful, paving the way for compensation claims against the Metropolitan Police.
The CPS said that 73 people charged with breaching the section 14 order, 24 charged with a breach and highway obstruction, and eight charged with stand-along highway obstruction would face no further action.
So far this year, policing protests by XR has cost the Metropolitan Police £40 million, nearly three times the annual budget of its Violent Crime Taskforce.
Raj Chada from law firm Hodge Jones and Allen said: "From the moment that the High Court ruled the Met Police's ban was unlawful, this was an obvious consequence.
"The CPS have dithered and delayed before bowing to the inevitable and only caused more anxiety and expense to our clients. "Anyone affected by this should contact us about a potential action against the police."
A spokesman for the Metropolitan Police said: "Following careful consideration and further legal advice, the Metropolitan Police Service (MPS) has decided it will not appeal the judgment in relation to conditions imposed on Extinction Rebellion 'Autumn Uprising'.
"The MPS remains disappointed by the judgment, but of course respects the decision of the court. We have previously stated public order legislation needs updating.
"This case is the first time the legislation has been tested in such unique circumstances. It has highlighted that policing demonstrations like these within the existing legal framework can be challenging.
"The MPS will continue to carefully consider and review the use of this legislation during future demonstrations."
Margaret Davis is the PA crime correspondent.