The extradition case of fugitive diamond merchant Nirav Modi, wanted in India on charges of fraud and money laundering, is expected to enter its final stages at Westminster Magistrates' Court in London on Tuesday.

The 49-year-old jeweller, fighting extradition in the estimated USD 2-billion Punjab National Bank (PNB) scam case, will appear via videolink from Wandsworth Prison in south-west London for the latest hearing in the case, during which District Judge Samuel Goozee will hear his defence team's arguments against the admissibility of certain evidence provided by the Central Bureau of Investigation (CBI) and Enforcement Directorate (ED) in order to establish a prima facie case against the accused.

The Crown Prosecution Service (CPS), arguing on behalf of the Indian authorities, will stress that the evidence meets the required criteria for the UK court to determine whether Modi has a case to answer before the Indian judicial system.

The jeweller is the subject of two sets of criminal proceedings, with the CBI case relating to a large-scale fraud upon PNB through the fraudulent obtaining of "Letters of Understanding" (LOUs or loan agreements), and the ED case relating to the laundering of the proceeds of that fraud.

He also faces two additional charges of "causing the disappearance of evidence" and intimidating witnesses or “criminal intimidation to cause death” added to the CBI case.

Tuesday's hearing follows two separate sets of hearings in the extradition case being presided over by Justice Goozee, the first in May and then in September, during which the CPS sought to establish Modi's fraudulent actions and played videos in court in support of the additional charges.

Assurances of adequate prison conditions were also provided by the Indian government, including further commitments of appropriate mental health care for Modi on being extradited.

The defence team, on the other hand, sought to not only establish that Modi's actions related to PNB-issued LoUs did not amount to fraud but also deposed witnesses to highlight his severe depression and deteriorating mental health behind bars. These were further ramped up at a bail hearing last week, when the court was urged to allow Modi to be shifted to a specialist facility under strict bail conditions.

However, Judge Goozee turned down the plea, reiterating the concerns from six previous bail attempts that Modi remains a flight risk who would abscond or interfere with the case if granted bail.

After this week's hearing to determine the admissibility of the evidence provided by the Indian authorities, it has been indicated that the case would move to a final hearing for the judge to hear the closing submissions in the case from both sides, either next month or early next year depending on the outcome of Tuesday's hearing.

A ruling by the District Judge, which would determine whether the case can be sent to UK Home Secretary Priti Patel to order Modi's extradition to India, is expected by next year, a few weeks after the final hearing.

Modi, meanwhile, remains in prison since he was arrested on March 19, 2019, on an extradition warrant executed by Scotland Yard. The charges against the diamond merchant centre around his firms Diamonds R Us, Solar Exports and Stellar Diamonds making fraudulent use of a credit facility offered by PNB or LoUs.

The CPS, on behalf of India, have told the court that a number of PNB staff conspired with Modi to ensure the LoUs were issued to his companies without ensuring they were subject to the required credit check, without recording the issuance of the LoUs and without charging the required commission upon the transactions.

Modi's team has sought to counter allegations of fraud by deposing witnesses to establish the volatility of the gems and jewellery trade and that the LoUs were standard practice. His family history of suicide and severe depression have also been raised as part of the arguments against extradition, which would make prison conditions at Barrack 12 in Mumbai's Arthur Road Jail inadequate for Modi's pre-trial incarceration in India.