Police are bracing for the possibility of mass protests and disorder over Tommy Robinson’s appeal result.

Backers of the far right leader have threatened to riot if he is not freed from prison by Court of Appeal judges on Wednesday, following violence and arrests at previous protests.

Metropolitan Police Commissioner Cressida Dick said the force had “made contingencies for potential issues”.

“We’ll see where the Free Tommy Robinson supporters go next and what they’re thinking next – it is a large set of people at the moment,” she told The Independent. “We are thinking about it and will be well-prepared.”

Ms Dick, who is Britain’s most senior police officer, said Scotland Yard had “excellent ways of monitoring all protest groups within the law, including our ability to keep in touch with them, and monitor what they are thinking and what they are talking about doing”.

The lord chief justice and two other justices will be ruling on claims by Robinson’s lawyers that he should be released because of alleged “procedural deficiencies” in two cases that led to him being jailed for contempt of court.

Robinson appeared at a hearing on 18 July via video link from prison and spoke only to confirm his real name, Stephen Christopher Yaxley-Lennon.

His barrister, Jeremy Dein QC, called on the judges to overturn contempt findings from May 2017 and May 2018 and to order Robinson’s release.

“There has been a conglomeration of procedural deficiencies that have given rise to prejudice and should lead to both findings being quashed,” he told the court.

Robinson was handed a three-month suspended sentence for attempting to film defendants at Canterbury Crown Court during a rape trial, which was activated and lengthened after he violated a blanket reporting restriction at Leeds Crown Court in May.

“He did not intend to breach any [reporting restriction] order, albeit that he was aware that there was an order,” Mr Dein told the court, claiming that Robinson was “operating as a journalist” and attempted to be legally vigilant.

Judge Geoffrey Marson QC said the English Defence League founder had admitted committing contempt of court in a Facebook Live video, which was broadcast for more than an hour and watched 250,000 times within hours of being posted.

The Court of Appeal heard that footage of Robinson discussing the ongoing case caused jury deliberations to be paused, sparking an attempt by defence lawyers to have jurors dismissed.

Mr Dein also claimed his client was effectively being held in solitary confinement at HMP Onley, with limited access to telephones, visits and rehabilitation activities.

But he acknowledged the restrictions had been imposed in “good faith” to protect Robinson from potential attacks by other prisoners.

The appeal was launched outside the 28-day time limit for challenging convictions, but was allowed because of delays to legal meetings.

Louis Mably QC, an independent barrister appointed by the attorney general to assist the court, said judges had to ask if any of the alleged procedural failings ultimately affected findings that Robinson had committed contempt of court.

The Tommy Robinson protest: in pictures Show all 27 1 /27 The Tommy Robinson protest: in pictures The Tommy Robinson protest: in pictures Protesters scuffle with police at the junction of Whitehall and The Mall during a 'Free Tommy Robinson' protest AFP/Getty Images The Tommy Robinson protest: in pictures A protester wearing a mask of US president Donald Trump was among thousands of supporters of far-right activist and former English Defence League leader Tommy Robinson staging a protest outside Downing Street in central London. Rex Features The Tommy Robinson protest: in pictures A man empties his beer over passing police AFP/Getty The Tommy Robinson protest: in pictures Supporters of English Defence League (EDL) founder Tommy Robinson demonstrate in Whitehall, London, Britain, June 9, 2018. REUTERS/Simon Dawson Reuters The Tommy Robinson protest: in pictures Dutch far-right opposition leader Geert Wilders addresses thousands of supporters Rex Features The Tommy Robinson protest: in pictures Demonstrators clash with police Getty Images The Tommy Robinson protest: in pictures Mandatory Credit: Photo by Clearpix/REX (9708609j) A demonstration has been held in Central London in support of Tommy Robinson. A large crowd of his supporters marched from Trafalgar Square to Downing Street. A counter demonstration was held some distance away and a large police force was present. Free Tommy Robinson protest, London, UK - 09 Jun 2018 Rex The Tommy Robinson protest: in pictures Protesters scuffle with police on Whitehall during a 'Free Tommy Robinson' protest on 9 June AFP/Getty Images The Tommy Robinson protest: in pictures Police watch supporters of Tommy Robinson PA The Tommy Robinson protest: in pictures People take part in a support rally for Tommy Robinson Rex Features The Tommy Robinson protest: in pictures Supporters of far-right spokesman Tommy Robinson demonstrate in Trafalgar square AFP/Getty Images The Tommy Robinson protest: in pictures Protesters scuffle with police at the junction of Whitehall and The Mall during a 'Free Tommy Robinson' protest on 9 June AFP/Getty Images The Tommy Robinson protest: in pictures A man climbs on one of the lions in Trafalgar Square Getty Images The Tommy Robinson protest: in pictures Protesters scuffle with police at the junction of Whitehall and The Mall AFP/Getty Images The Tommy Robinson protest: in pictures Police clear supporters PA The Tommy Robinson protest: in pictures Beer is thrown as demonstrators clash with police Getty Images The Tommy Robinson protest: in pictures Demonstrators clash with police Getty Images The Tommy Robinson protest: in pictures Demonstrators clash with police Getty Images The Tommy Robinson protest: in pictures Protesters scuffle with police AFP/Getty Images The Tommy Robinson protest: in pictures Demonstrators clash with police Getty Images The Tommy Robinson protest: in pictures Demonstrators clash with police Getty Images The Tommy Robinson protest: in pictures Demonstrators clash with police Getty Images The Tommy Robinson protest: in pictures Demonstrators clash with police Getty Images The Tommy Robinson protest: in pictures Supporters of English Defence League (EDL) founder Tommy Robinson clash with the police in Whitehall, London on 9 June Reuters The Tommy Robinson protest: in pictures An injured police officer during a 'Free Tommy Robinson' protest in London on 9 June AFP/Getty The Tommy Robinson protest: in pictures Protesters take over a sight-seeing bus on at the junction of Whitehall and The Mall during a 'Free Tommy Robinson' protest on 9 June AFP/Getty Images The Tommy Robinson protest: in pictures Police watch supporters of Tommy Robinson during their protest in Trafalgar Square PA

He said the case was a question of “substance not form”, adding: “There is nothing in the rules to suggest an order or finding of contempt is invalidated if a particular aspect of the rules is not complied with.”

Police officers kept a watchful eye on a small group of “Free Tommy” protesters who gathered outside the Royal Courts of Justice during the hearing, as other supporters sat in the court.

MPs and campaigners have warned that far right extremists are using the case as a rallying point to create a new “racist street movement”, amid rising hate crime and Islamophobic attacks.

Protests have taken place around the world since the 35-year-old was jailed but the largest have been in London, where supporters performed Nazi salutes and attacked police officers in June.

Earlier this month, a “Free Tommy” protest merged with a pro-Donald Trump march during the US president’s visit to the UK.

Demonstrators were condemned for blocking a bus driven by a Muslim woman during the event, which included speeches by Ukip leader Gerard Batten, Dutch opposition leader Geert Wilders and other populist figures.

A neoconservative US think-tank has claimed it funded both protests and Robinson’s legal costs, while his former employers at Rebel Media are also crowdfunding in his name.

Robinson has been forming links with the American alt-right, which characterises him as a “citizen journalist” and his imprisonment as a violation of freedom of speech.

Lobbying by the far right Breitbart news website reportedly caused the US ambassador for international religious freedom to raise Robinson’s case with the British government.