Yvette Cooper wrote a newspaper column about Palestine Action despite prosecutors warning it could prejudice criminal proceedings against six activists from the group, it can be revealed.

The then-home secretary wrote the column justifying Palestine Action’s proscription even though the Crown Prosecution Service advised it might unfairly impact a trial concerning a 2024 break-in at an Israeli arms manufacturer’s factory.

After a retrial, four of the defendants were convicted last week in relation to the raid on the Elbit Systems UK site near Bristol. It can now be reported that defence lawyers sought to halt the proceedings for alleged abuse of process, claiming Cooper’s column for the Observer was “an egregious example of contemptuous reporting which directly interferes with the court process”.

The article, on 17 August, said that charges against Palestine Action activists included a “terrorism connection” and also referred to violence, intimidation and “disturbing information” about future attacks.

In written submissions arguing that a fair trial would be impossible, the defence lawyers said the article was “dripping in innuendo. In one breath, she is saying that many important details cannot yet be publicly reported; in another, she is reporting some of those very details herself”.

In a pre-trial ruling last November, Mr Justice Johnson said: “It is to be taken that the home secretary was specifically advised that going ahead with the article might prejudice these proceedings, and that she went ahead anyway … The CPS made representations to the home secretary about the risk of prejudice. It follows that the home secretary took the action that she did, and made the public statements that she did, in the knowledge that these proceedings were extant and that there might well be a question as to the impact of her conduct and her statements on these proceedings.”

However, Johnson dismissed the defence application for abuse of process, saying: “The decision to proscribe Palestine Action was highly controversial and required public justification. It is unsurprising that the government sought publicly to justify the decision that it had taken and that it relied, in general terms (without naming individuals), on Palestine Action’s activities, including the activities that have resulted in these proceedings.

“In doing so, the home secretary ran a risk of causing some prejudice to these proceedings, but that is different from deliberately flouting a reporting restriction order.”

In arguing that there were “false and irremediably prejudicial public statements made by the government when seeking to justify proscription”, defence lawyers cited other articles, including a report in the Times that Home Office officials claimed Iran could be funding Palestine Action. The Home Office later distanced itself from the claim, which Johnson described as “misleading”.

The defence team also claimed there had been an abuse of process in the charges against the defendants having a terrorist connection, claiming that the authorities wanted to ban Palestine Action and “they were aware that this could not be done without pursuing terrorism related charges”. The jury was not told during the trial about the terrorist connection allegation, which could have resulted in Charlotte Head, 29, Samuel Corner, 23, Leona Kamio, 30, and Fatema Rajwani, 21, receiving much harsher sentences on 12 June for criminal damage.

The third and final ground for abuse of process alleged “collusion between the government and the Israeli state, Elbit Systems and the pro-Israeli lobby regarding the proscription”, citing meetings and/or communications involving the named parties.

Johnson ruled there was no political interference in the charging decision and that the communications with groups outside government did not come close to establishing improper conduct.

A Home Office spokesperson said: “The judge concluded that the article did not prevent a fair trial taking place.

“The trial found four Palestine Action members guilty of criminal damage, and one was also found guilty of grievous bodily harm.”