A Greenpeace activist from Oxford was among 10 whose oil terminal protest forced a tanker carrying Russian diesel to U-turn in the River Thames.

Zoe Pontida, 32, and her nine co-defendants were cleared of aggravated trespass, with a judge saying Russia's war in Ukraine ‘could be described as terrorism’.

The defendants, aged between 27 and 72, claimed they were ‘preventing a crime’ by occupying a jetty at Navigator Terminals in Grays, Essex, preventing the vessel from unloading the diesel.

District judge Christopher Williams, who returned his judgment at Chelmsford Magistrates' Court on Friday, said: "I take the view it's more than likely the Russian war could be described as terrorism."

Speaking after hearing, teacher Zoe Pontida, of St Clements, Oxford, described the verdicts as ‘seismic’.

"It doesn't just fully vindicate our action, it also puts the UK government squarely in the dock,” she told the Press Association.

"The judge has recognised that we are just ordinary people whose conscience compelled us to stop the oil funding Putin's campaign of state terrorism in Ukraine."

The 10 defendants had denied, and were each cleared of, a single charge of obstructing or disrupting a person engaged in a lawful activity under the Criminal Justice and Public Order Act 1994.

The charge said that they trespassed on land at Navigator Terminals and blocked the jetty, obstructing or disrupting ‘a lawful activity, namely fuel distribution’.

Henry Blaxland KC, defending, questioned whether the unloading of the Russian diesel was lawful activity, and the judge said that ‘in my view the unloading of the oil was the potential offence’.

The protesters broke out into applause and there were cheers as the judge found each of them not guilty.

Prosecutor Monali Raleraskar argued that the case did not ‘require an analysis of what's morally right and what's morally wrong’.

But the judge said it was ‘arguable that offences may have been committed under the Terrorism Act 2000’, and that the ‘activity which the defendants disrupted was the very thing they were protesting about’.

The protesters took two dinghy boats to access the jetty from the riverside late on May 15 this year.

Activists attached themselves to the structure and displayed a banner that said "oil fuels war".

The Andromeda tanker, which was Greek-flagged and carrying Russian oil, was turned around in the Thames in the early hours of May 16.

One of the activists who scaled the jetty, former lieutenant colonel Michael Grant, 62, told the court: "The purpose of the action was to draw attention to the fact that fossil fuels were being imported and thereby funding Putin's war."

Speaking afterwards, Mr Grant said: "This is a fantastic result.

"This verdict is not just a relief for us but a complete vindication of the ethical beliefs that led us to act."

The defendants were: Benji Bailes, 38, of Gloucester; Michael Grant, 62, of Rosewell, Midlothian; Kim Harrison, 38, of Oldham, Greater Manchester; Benjamin Hearne-Salter, 41, of Kashmir Road, south London; David James, 62, of Bromfelde Road, south London; Ian Mills, 56, of Chippenham, Wiltshire; Zoe Pontida, 32, of Oxford; Henry Rayner, 28, of Ivanhoe Road, south London; Lyndall Stein, 72, of Surrey Row, south London; Rhiannon Wood, 27, of Hedge End, near Southampton, Hampshire.