Extinction Rebellion threatened to shut down the airport in a protest against its planned expansion.Read more
London climate change protests
Responding to a question about whether reports are correct that the Met are trying to charge every person who was arrested during the Extinction Rebellion protests, Sir Stephen House told the committee the force were "looking to proceed against them" but "not necessarily looking to charge all of them."
The deputy commissioner said not all of those who were held during the demonstrations had been interviewed so the Met were looking to do that now.
When asked whether the action was proportional, Sir Stephen said large parts of London had been brought to a standstill while the economy "lost an awful lot of money".
"People broke the law with impunity. If they break the law there has to be consequences", he said.
Sir Stephen also told the committee the police were never short of cells for holding protesters but the main problems were a lack of interview rooms and the fact that nearly all the protesters used only two solicitor firms which further slowed down proceedings.
The London Assembly Police and Crime Committee is holding a question and answer session with Sophie Linden, the deputy mayor for policing and crime in London, and the Met's Deputy Commissioner Sir Stephen House.
The hearing began with questions about the police response to the Extinction Rebellion protests over Easter.
Sir Stephen told the committee the protests were "the first of their kind" and "it was something we haven't ever dealt with in terms of the volume and tactics".
The deputy commissioner said the force had "learnt lessons" such as deploying greater numbers of officers more quickly and "will take action quicker".
Sir Stephen also dismissed claims that the Met had been made to look like a "laughing stock" by the protesters and said 520 letters had now been sent out requesting that people who had been arrested during the demonstrations come to a police station for an interview.
"We intend to build the cases against all of those who were arrested", he said.
After a mural appeared at Marble Arch the artist may have been at the Extinction Rebellion protest.