Britain has created a new breed of political prisoners through the systematic incarceration of people acting to prevent climate breakdown and the annihilation of Gaza, a report claims.

The research by Queen Mary University of London (QMUL) and the protest group Defend Our Juries says that custodial sentences for acts of direct action or civil disobedience were once rare but are now being imposed with increasing length and frequency.

Their report, which will be launched on Tuesday, points to an increase in anti-protest legislation in England and Wales, police powers and civil law injunctions brought by corporations and public bodies as well as judges removing legal defences and “exceptionally long” sentences.

In what they say is the first analysis of the jailing of “Britain’s new political prisoners”, the researchers identified 286 cases involving climate and Palestine-solidarity activists who were sent to prison for protest for a total amount of jail time of 136 years.

The average detention period in the 256 cases for which data was available was 28 weeks, with one in three protesters jailed for six months or more and one in five for more than a year.

David Whyte, the report’s co-author and professor of climate justice at QMUL, said: “These are exceptional sentences that are being used to apply to protests which are themselves profoundly political.

“So it’s clear that extreme sentences and the level of remand detentions [before trial] at an extreme level are being used to respond to one category of prisoners and that’s prisoners who’ve been detained because they’ve been involved in civil disobedience, direct action as a result of political protest. So there is something going on which is profoundly political. Very often those protesters are reflecting majority rather than a minority view.”

The report describes remand as “the first line of attack”, with the effect of chilling protest and civil disobedience. The researchers found that in 60% of cases, final sentences were more lenient than time already spent in custody awaiting trial. They highlight the “Filton 24”, who were charged with offences connected to a Palestine Action direct action protest at a factory near Bristol run by the Israeli weapons manufacturer Elbit Systems.

The accused spent up to 18 months in jail – the standard pre-trial limit is six months – before all but one were bailed after the first set of six defendants were cleared of aggravated burglary. Two out of those six were subsequently acquitted of criminal damage. Eighteen more defendants due to stand trial over the events at Filton still face other charges.

Contempt of court, where there is no jury trial, was found to account for 40% of cases of imprisonment. Contempt charges either arise from the conduct of a defendant in the courtroom, including where an order of a judge is breached (8% of total imprisonment cases), or where a civil injunction obtained by a private company or public authority to prevent protest is breached (32% of cases).

Whyte said: “The real danger is that you criminalise people for breaching something which is essentially a civil injunction. So that doesn’t start as a criminal offence but it ends up with a criminal penalty and that’s very concerning because it means that private companies, effectively, are imposing injunctions which lead to large numbers of people going to jail.”

The report found that 69 people were imprisoned, including some for holding placards, after North Warwickshire borough council obtained a high court injunction in 2022 in response to Just Stop Oil’s direct action campaign at Kingsbury oil terminal.

A judicial spokesperson said: “Judicial independence and impartiality are fundamental to the rule of law. Upon taking office, judges take the judicial oath where they swear to act ‘without fear or favour, affection or ill will’. In each case, judges make decisions based on the evidence and arguments presented to them and apply the law as it stands.

“Judges and magistrates sentence according to the law set by parliament and the sentencing guidelines set by the independent Sentencing Council, as well as the facts of each case which may have aggravating or mitigating factors.”