More than 680 climate change protesters were arrested by the police. The Met said they wanted to restore business as usual at London's Oxford Circus.
The protests are now on their sixth day when the Met wanted to admit they had to fight for room in the cell because of the large number of demonstrators arrested.
A police spokesman for Met said, "We have set up a very robust police response plan at Heathrow to ensure that families and people who want to go to the Easter break or even visit London can do so without interruption.
"What is unusual about this demonstration is the willingness of those involved to be arrested, as well as the lack of resistance to the arrests.
"To date, we've made over 680 arrests, which of course is a logistical problem, not just the cell-room police service, but the entire criminal justice system."
The police saw in London's Oxford Circus this morning how they tried to attack demonstrators and warned that people would not be demonstrated in places other than Marble Arch.
Yesterday, the pink boat was blocked with activists from the Extinction Rebellion to block Oxford Circus.
Lady Emma Thompson has brought together Extinction Rebellion (XR) cheering activists to block London's busiest shopping street, declaring, "Our planet is in serious trouble."
The Oscar-winning British actress climbed onto the boat to tell the masses that "our planet is in serious trouble."
She said, "We are here on this little island of reason and it makes me so happy that I can join all of them and add my voice to the young people who have inspired a whole new movement."
She read a poem by writer and illustrator Jackie Morris, who was asked to write a "Letter to the Earth".