The nine protesters who brought London City Airport to a standstill, grounding more than 100 flights with a so-called Black Lives Matter protest at London City Airport have been sentenced for breaching airport security.

But the judge said she found it “rather hard” to make a link between the Black Lives Matter campaign, which highlights mistreatment by US police, and climate change, the cause of the, mostly white, protesters.

They erected a tripod and locked themselves together on the runway after apparently rowing to the airport over the Victoria Dock, London’s Westminster Magistrates’ Court heard.

The nine protesters all pleaded guilty to aggravated trespass by disrupting a person engaged in a lawful activity and were all given an 18-month conditional discharge except for two defendants who had convictions for previous similar protests.

A police dinghy sails past as aircraft stand idle at City Airport after a protest closed the runway causing flights to be delayed

District judge Elizabeth Roscoe said: “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 the protest had caused “a lot of disruption to a great many people” including those “who may have had similar beliefs to yourself”.

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She said creating a disturbance at 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 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.

They must all pay £95 prosecution costs.