A protest about environmental racism paired with an airline technical problem combined to disrupt traffic at three of London's airports, prompting complaints, arrests and delays Tuesday.
The main focus was on a group of nine activists - allegedly from the Black Lives Matter UK organization, according to press reports - who chained themselves to an object on a runway at London City Airport, according to the airport and London police.
"We're currently experiencing disruption to all flights due to protesters at the airport," tweeted the airport. "Police are currently on the scene."
Metropolitan Police reported that seven of the protesters had been arrested on trespassing charges, but only two removed. Police noted that work continues to remove the rest.
It was not clear what connection the protesters had to the US-based Black Lives Matter movement, which protests police violence in the United States targeted at black people.
A Twitter account believed to belong to the demonstrators said they were protesting climate change, which is exacerbated by jet fuel emissions and which has a disproportionate effect on black people in Africa.
Separately, delays were reported at London's Gatwick and Heathrow airports after carrier British Airways said a computer upgrade was causing problems.
The airline said it has fixed the problem, but that it might take a while to process the backlog of passengers affected by the delay.