Nine people who took part in the Black Lives Matter protest that grounded up to 131 flights at City Airport last week have been sentenced for the “serious” matter of breaching airport security.

They locked themselves together after storming the single runway of the east London airport on September 6 at around 5.30am, London’s Westminster Magistrates’ Court heard.

District judge Elizabeth Roscoe told the defendants, who all stood in the dock as they were sentenced, that she believed they all had deeply-held views particularly about climate change but that she found it “rather hard” to make the link with the Black Lives Matter campaign which stems from alleged racist treatment by the police in the US.

The nine protesters all pleaded guilty to aggravated trespass by disrupting a person engaged in a lawful activity when they appeared in the dock at the central London court.

All were given an 18-month conditional discharge except for two defendants who had convictions for previous similar protests, and must all pay £95 prosecution costs.

The judge told them: “There is a right in this country to protest and to protest peacefully.

“It was a peaceful although disruptive protest.

“I find it rather hard to see the link between the protest movement which started in America and goes by the name Black Lives Matter which as I understand protests against the treatment of the black population by the police in America.

“I am not sure how that links to City Airport and climate change. I do not underestimate the sincerity of your beliefs.”

She said going into a secure area in an airport “does cause concern to the public”.

The judge said: “To put fears and doubts in minds that these areas are easily accessible not just to you but to people with less peaceful intentions is serious. I do not think that this was in any way a minor matter.”

Deborah Francis-Grayson, 31, of St Mary’s Road, Slough, was given a three-year conditional discharge while Alex Etchart, 26, who lives on a houseboat called the Northern Soul, was given a two-year conditional discharge.

The other defendants were William Pettifer, 27, of Radford Mill Farm, Radford; Esme Waldron, 23, of Walmer Crescent, Brighton; Sama Baka, 27, and Sam Lund-Harket, 32, who live on the Northern Soul; Natalie Fiennes, 25, of Thurleigh Road, Wandsworth; Richard Collet-White, 23, of Spring Road, Kempston; Ben Tippet, 24, of Thurleigh Road, Wandsworth.