New Delhi | The Congress on Thursday termed "erroneous and unsustainable" a Surat court judgement rejecting Rahul Gandhi's appeal in a defamation case related to his "Modi surname" remark, and said the judge seems "over-shadowed" by the high office of the prime minister.

Congress senior spokesperson Abhishek Singhvi said they would move the High Court "very shortly" as the judgement is "fallacious" and contrary to all basic principles of law.

The court of Additional Sessions Judge R P Mogera rejected Gandhi's application for a relief against a magisterial court order sentencing him to two years in jail in the defamation case.

"A most unfortunate and unsustainable legal decision of the magistrate has been upheld in an even more unsustainable and erroneous judgement of the Sessions court given today. The conviction has been upheld contrary to all basic elementary principles of law," Singhvi told reporters at a press conference.

"Let me assure you that the judgement will be challenged in accordance with law in the very near future," he said.

Arguing that the judgement is "wrong" with no legal standing, he said the court has noted that Prime Minister Modi has been defamed along with 13 crore others with the Modi surname, which shows that the judge is "over-shadowed" by the exalted office of the prime minister.

"Clearly, unfortunately the judgement is influenced by the high office of the prime minister, forgetting that the honourable prime minister is not the complainant," Singhvi said.

Sources said that Singhvi, himself a noted lawyer, is likely to appear before the High Court in Gujarat while challenging the Sessions Court order.

"There is a legal error in the judgement. We respect all courts and we have the High Court and Supreme Court. We have several grounds to challenge the judgement.

We will move the high court in the very near future," Singhvi said.

"We are confident that superior courts with constitutional power of judicial review, namely the High Court and the Supreme Court, have the power and will set right the legal errors found in these two judgements. We are clear that the judgement in devoid of valid sustainable legal reasoning," he said.

Singhvi said the one-line remark of Rahul Gandhi in a two-and-a-half page speech "has been from inception distorted completely out of recognition to serve the narrow ends of motivated complainants, that has been hardly interpreted in the sessions court judgement and what little has been said is a complete distortion, legally erroneous".

Gandhi had on April 3 approached the sessions court for appeal against the lower court's order.

Training his guns on the BJP government, Singhvi said, its "speed and zeal" to act after the magistrate's original order show "they are motivated by political animosity from house taking, to electricity connection disconnection to notices etc".

Their completely misleading and displaced statements about the OBCs have backfired on them and the entire community and the whole of India now see the BJP as using the OBC community for narrow and cheap political games, he said.

"The voice of Rahul Gandhi is not to be silenced in the manner in which the BJP thinks it can do. The BJP has been in a sense from Mr Modi downwards to the government and the ruling party captured in a fear psychosis," he said, alleging the ruling party has unleashed lakhs of trolls against the former Congress president.

"They sometimes threaten you with privilege notices, sometimes it is suspension, but they do not know the stuff Rahul Gandhi is made of. They do not know the resilience of the Congress party. His voice will not be silenced because he speaks to the court of people.

"He did not speak anything which is remotely defamatory in this case... he will continue to speak fearlessly in the court of the people. Clearly these pressure tactics from defamation, privilege notices to not (allowing him) to speak in Parliament to suspension etc are intended to silence his strong, fearless voice on issues of misgovernance, on corruption, on Adani-gate etc," the Congress leader said.

After his conviction by the magistrate court on March 23, Gandhi was disqualified as Lok Sabha MP and he was asked to vacate his official bungalow.

A stay on the conviction by the sessions court could have paved the way for his reinstatement as Member of Parliament.

The lower court had sentenced him to two years in jail while convicting him for criminal defamation over his remark, "How come all thieves have Modi as the common surname?" made during an election rally at Kolar in Karnataka on April 13, 2019.