The 61-year-old has claimed, via his legal team, that the case brought against him is "politically motivated" and that it was being used as an opportunity to make "political capital" by the ruling BJP as well as Congress and Shiv Sena.
"CBI has a long and inglorious history of being politically motivated in cases with a direct correlation between allegations of corruption and election years," his barrister Clare Montgomery had claimed in the Westminster Magistrate's Court on Tuesday.
The CBI team in London for the case, led by Special Director Rakesh Asthana, was present in court during this claim.
Laying out her counter-arguments before Judge Emma Arbuthnot, Clare Montgomery had also called into question the "admissibility" of some of the evidence submitted by the Crown Prosecution Service (CPS) on behalf of the Indian government.
She claimed that much of the material was questionable and there were at least a dozen documents submitted which read like an identical "template".
The judge has asked both sides to submit a document laying out the factors for and against the admissibility of the evidence submitted by the Indian authorities by the end of this week.
While the defence claims there is "zero" evidence to support a credible case of fraud against Mr Mallya, the CPS had opened the trial on Monday with a detailed chronology of events to show "by virtue of evidence a prima facie case" against the boss of the now-defunct Kingfisher Airlines.
The prosecution's case rests on "three chapters of dishonesty" by Vijay Mallya's misrepresentations to various banks to acquire loans, the misuse of the loans and his conduct after the banks recalled the loans.
The charge of money laundering, for which Mr Mallya had been re-arrested in October, is being focussed on less at this stage with fraud being central to the CPS case.
Today's hearing, expected to take place over some "interruptions" while Judge Emma Arbuthnot attends to other cases, is likely to focus on the testimony of a financial sector expert referred to in court as Mr Rex.
He will be the second defence witness to take the stand, following aviation expert Dr Humphreys, who had been brought in on Tuesday to support the defence argument that there was no intentional fraud involved in the default on bank loans by the then struggling Kingfisher Airlines.
Mr Mallya, who has been living in the UK since March 2016, was arrested by Scotland Yard on an extradition warrant in April this year and has been out on bail on a bond worth 650,000 pounds.
His extradition trial is scheduled to end on December 14, with Friday marked as non-sitting day. A timeframe for a judgement in the case will be determined at the end of the trial after closing arguments have been made.
If the judge rules in favour of extradition at the end of the trial, the UK home secretary must order Mr Mallya's extradition within two months.
However, the case can go through a series of appeals in higher UK courts before arriving at a conclusion.