Political blogger Mike Sivier has been denied permission to appeal his loss in a defamation case brought by Rachel Riley after he wrote an article accusing her of abusing a 16-year-old girl on social media.

The Countdown star sued Mr Sivier over a 2019 article about a Twitter debate on antisemitism in the Labour Party under Jeremy Corbyn's leadership, which Ms Riley said had triggered online abuse.

Mr Sivier had claimed that his article was in the public interest, however in her ruling last November, Mrs Justice Steyn said that although Mr Sivier believed and continued to believe that his article was in the public interest, that belief was "wholly unreasonable" that had no basis in the evidence, and Ms Riley was awarded £50,000 in damages.

Mr Sivier announced almost immediately that he intended to pursue an appeal, however Lord Justice Warby today rejected the application after hearing arguments from both sides.

Mr Sivier's legal team argued that the reasoning behind Mrs Justice Steyn's conclusions was unsound and, in some respects, incomplete, and that there were errors of law. He sought to reverse the decision and have a retrial.

But speaking in court today, Lord Justice Warby said: “My overall conclusion is that, for reasons I will give in detail in writing, none of the three grounds of appeal is properly arguable with a real prospect of success. For those reasons, permission to appeal is refused.”

Following the judgement, Libel lawyer Mark Lewis, who represents Ms Riley, told the JC: “The door is now slammed shut on this case. Mr Sivier drove this case, and could have backed out very early on by apologising, and paying a nominal amount.

"Rather than doing that, many vulnerable people have crowdfunded quarter of a million pounds to pay his solicitors and barrister when such money could have been put to much better use in these desperately hard times.

"Neither, Rachel’s barrister nor Patron Law (Mr Lewis' firm) will see a penny for defeating this persistent abuse of the legal process. The irony, in this case, is that Mr Sivier has portrayed himself as poor and vulnerable, whereas in fact he has outspent Rachel by approximately £250,000.”

The case was brought following an article published on Mr Sivier's website Vox Political on 26 January 2019 with the headline “Serial abuser Rachel Riley to receive ‘extra protection’ – on grounds that she is receiving abuse”.

The article centred around Twitter exchanges in December 2018 and January 2019 between Ms Riley and a girl who identified herself as a 16-year-old named Rose. Mr Sivier claimed in his article that Ms Riley was a "serial abuser" and these exchanges amounted to abuse.

Giving evidence at the trial last year, Ms Riley spoke about the volume of abuse that she had received as a result of the article, saying: "I changed my Twitter settings after that week because it was so horrendous."

The judge found that Ms Riley had been a "credible and reliable witness", while Mr Sivier "came across as intransigent" and therefore the judge "found his evidence to be unreliable."

In the original case, Mr Sivier's legal team had argued that Ms Riley had not suffered serious harm from the article, saying that she was already known for being "highly offensive and controversial".

However, Mrs Justice Steyn dismissed those claims about Ms Riley's behaviour following an analysis of the Twitter exchanges given in evidence.

The judge described Ms Riley's tweets in reply to Rose as "gentle, civil and measured", which she added was "in sharp contrast to the insulting messages some other Twitter users had sent Rose, and manifestly provided no encouragement to anyone to abuse, bully, or harass her."

Of the first Twitter thread, the judge wrote: "Ms Riley clearly sought to discourage anyone from attacking Rose by accepting unequivocally, at the outset of the thread, Rose's statement that she would never be racist to anyone and condemns antisemitism, and by stating at the end of the thread that she knew Rose's 'heart is in the right place', expressing the view that 'online pile-ons can be horrible' and stating that anyone attacking Rose could 'f the F off'."

"Mr Sivier's evidence that in the second thread, Ms Riley made a further attempt to gaslight Rose, and that by contacting her on public Twitter, rather than using the direct message system, Ms Riley sought to intimidate, abuse and harass Rose again bears no rational relation to the messages that she sent."

"In his statement, Mr Sivier asked, 'What possible reason could she have had for publishing this thread, other than to create animosity against the girl who had challenged her?' The answer was patently obvious: her reason for publishing the 9 January thread was to defend herself against an unfounded allegation of bullying a 16-year-old girl online."

On damages, the judge said: "There has been no retraction, amendment or apology to mitigate the damage to the claimant’s reputation or to provide any element of vindication. The award of damages, together with this judgment, will have to provide that.”

The judge determined that there is an "irresistible case" for an injunction requiring the article to be taken down, and preventing Mr Sivier from publishing those claims or similar ones.

Ms Riley's team had asked for damages of £156,000 and Mr Sivier's lawyers said that they should amount to "no more than nominal damages and 'no sum close to the £10,000" awarded in Riley v Murray.

However, the judge determined that £50,000 was a reasonable award.

For the initial case, Mr Sivier had appealed online for financial assistance, raising £233,830 of a target of £250,000. After he announced his intention to appeal, he continued to fundraise, and at the time of publication, he has raised £247,915 of a new target of £300,000.

Mike Sivier has been approached for comment.