|Singh's government has been bogged down in corruption allegations for much of its second term [GALLO/GETTY]
A corruption trial has begun with a former government minister accused of playing a central role in a massive scandal over the allocation of mobile phone licences.
A Raja, who was telecoms minister from 2007 to 2010, is the central figure in a case that has rocked Manmohan Singh's administration and helped make corruption one of the country's hottest political issues.
The sale of second-generation (2G) licences at far below their commercial rate to selected companies could have cost the treasury up to $39bn in lost revenue, according to the public auditor.
The 48-year-old Raja, a member of the DMK, a crucial regional party in the Congress party-led coalition, appeared in court on Friday alongside the other defendants from the senior ranks of telecom companies and the bureaucracy.
The 14 parties accused face charges including criminal breach of trust, bribery, forgery and cheating.
The trial, being held at a CBI special court in New Delhi, is expected to be a lengthy affair due to the complexity of the case, the number of accused and India's extremely slow legal system.
"This is the start of what's expected to be a fairly long trial. It has taken months for federal investigators to piece together the evidence for the trial to actually begin today," Al Jazeera's Prerna Suri reported New Delhi.
The charges against all the accused vary, she said.
"The minister has been charged with favouring private companies during the process of allocating mobile phone spectrum licences. ... The other accused have been charged with paying kickbacks to the minister as well as several of the officials," she said.
The judge called on Friday for the first prosecution witness, Anand Subramaniam from Reliance Capital, part of a group owned by Anil Ambani, a leading Indian industrialist.
The prosecution is likely to focus on accusations that when allocating the licences Raja favoured Swan Telecom, alleged to be a front for Ambani's Reliance group, and another company called Unitech Wireless.
"We will focus on the incorporation [of Swan], and then on the events that unfolded in the department of telecommunication. In the later stages, the trial will focus on beneficiaries of the scam," a prosecution source told the AFP news agency.
Raja, 48, was denied bail when he was arrested in February and has spent the last nine months in Delhi's Tihar jail along with several other suspects.
Others accused of wrongdoing include Kanimozhi - a parliament member known by one name who is the daughter of the DMK chief, M Karunanidhi - plus senior telecom executives and government officials.
Kanimozhi's lawyers insist that while she was politically close to Raja, she did not benefit from his alleged manipulation of the auction system.
"They are very confident that they have not done anything illegal or wrong so they will come out clean," TKS Elangovan, a DMK politician, told the NDTV news channel. "The prosecution will find it difficult to prove the charges."
The accused all deny any wrongdoing. They face a maximum sentence of life in jail if found guilty.
"The government is quite keen on showing that they are quite serious about bringing the guilty to justice but on the ground people have their looming doubts and feel that the bigger game players may be shielded from all of this," Al Jazeera's Suri said.
"This is a very politically loaded case. When Mr Raja was arrested, he made claims and allegations that all the decisions he made as a union minister was with the full knowledge and support of the prime minister as well as the present finance minister.
"It would be quite interesting to know whether the judge would call in these ministers for questioning. And if that happens it is going to add further political ammunition to India's opposition."
The case, one of the biggest in independent India's history, has led to intense pressure on Singh and many observers believe the trial could expose leading politicians and businessmen to damaging revelations.
Corruption in public life has become a burning issue in Indian politics, with large protests in August triggered by a hunger strike in New Delhi by Anna Hazare, a social activist.