If Britain’s far right were looking for a new cause célèbre after last year’s Southport killings, many believe they have found it in the case of Lucy Connolly.

The childminder and wife of a Conservative councillor from Northampton was jailed for 31 months in October after calling for hotels housing asylum seekers to be torched.

Yet the failure last week of her attempt to appeal against the sentence has only reinforced her standing as a martyr among far-right activists who have raised thousands through fundraising campaigns.

At the same time, Reform UK and mainstream Conservative voices and media portray her as the latest victim of a “two-tier” justice system that they say treats offenders from some backgrounds more favourably. Lobbying has reached the Trump administration, where the US state department says it is monitoring the case, referring to its concern about “infringements on freedom of expression”.

Funds raised for Connolly in Britain include £40,000 raised by Reclaim the Media – a company set up by the far-right agitator and former actor Laurence Fox.

Patriotic Alternative, one of Britain’s most active far-right groups, told supporters it gave her family £1,000 from a fund established for what it described as “political prisoners”.

At the same time, the judge who sentenced Connolly has become a target of abuse. Social media posts included one by a far-right influencer who mocked up a photograph of the judge under the heading: The Banality of Evil: Who is Lucy Connolly’s Anti-British, Woke Judge?’

“Death Penalty” replied an X user with a blue tick.

Concerns have been expressed by the Law Society, which told the Guardian: “Attacks on the legal profession undermine the rule of law and can have real-life consequences.”

“In recent years, negative language used by politicians and the media about legal professionals has seen waves of online hate and death threats causing many lawyers to seek police protection,” said Richard Atkinson, the president of the Law Society of England and Wales.

“During the riots last summer, 39 law firms and advice centres were targeted. Nobody should be put at risk for doing their job, least of all when that job is to uphold the law.”

There is also unease at the tone and language used by more high-profile figures on the right, including Boris Johnson, who claimed Connolly’s case showed Britain was becoming a “police state”.

Charlie Falconer, a Labour peer and former justice secretary, condemned the remarks, adding: “Attacking the law and the judges who give effect to it is a cowardly and deceptive way of trying to justify despicable criminal conduct.”

There is now also concern within Labour about the potential of the case to gain traction among the general public. Mary Glindon, a Labour MP, broke ranks on Thursday to join Conservative MPs in signing a motion of support for Connolly from Rupert Lowe, the former Reform UK MP who used prime minister’s questions to raise the case.

Glindon said she had signed the motion because she was upset Connolly had lost her appeal, adding that her young daughter would continue to be without her mother. While backing the judge, other Labour MPs have privately expressed concern about how the case could be exploited.

For now, the Tory leader, Kemi Badenoch, has resisted the urge to echo the exact “two-tier” language of Reform and others, saying instead that Connolly had been treated unfairly and there was a perception of bias that was “fuelling radicalisation”.

But a Conservative strategist likened the case to the controversy surrounding the new guidance around sentencing of offenders from ethnic minorities. They also noted: “Unusually, this is a case in which the alt-media has had real cut-through on it.”

Connolly, meanwhile, is expected to remain in prison until August, although the campaign in support of her continues. Her most high-profile backer has been the Free Speech Union, the libertarian organisation founded by the Tory peer Toby Young, which has funded her legal team. It says the public reaction to the campaign has been “off the charts”.

At the heart of the case is an X post in July last year that changed Connolly’s life forever. “Mass deportation now, set fire to all the fucking hotels full of the bastards for all I care … if that makes me racist so be it,” she tweeted to 9,000 followers, after three girls were killed in a knife attack at a holiday club in Southport.

In a written judgment published last Tuesday, an appeal court judge said: “There is no arguable basis on which it could be said that the sentence imposed by the judge was manifestly excessive.”

Responding to Lowe on Wednesday, Starmer backed the courts, stating he is “against incitement of violence to other people” and stressing that sentencing was a “matter for our courts”.

Connolly’s husband, Raymond Connolly, used an interview on GB News on Friday to accuse the prime minister of having “picked” his wife as “the poster girl of the far right”.

“We’ve got a government who are just doing what they want to do,” he said, denying she was far right and accusing Starmer of “total intimidation”.

In strictly legal terms, experts point out that Connolly’s sentence was severe because inciting racial hatred is one of the most serious offences under hate crime legislation. Connolly had also pleaded guilty.

Sunjay Versani, the director of crime and prison law at Duncan Lewis Solicitors, said the court considered the likely impact of the message and whether it was capable of encouraging others to hate. Factors included the public nature vulnerability of the target and absence of credible mitigation, despite her expression of regret.

“There has been plenty said about the sentence being too severe. However, the reality is the term is properly in line with sentencing guidelines,” he added.

“One of the reasons they exist is to ensure uniformity … so the same sentence for the same criminal conduct is handed down, regardless of whether you’re in London, Leicester or Leeds.”