The CBI has sought sanction from Lok Sabha Speaker Om Birla to prosecute three sitting Trinamul Congress MPs and a former parliamentarian of the party in the Narada scandal, sources in the agency said on Thursday.

The three MPs are Saugata Roy, Kakoli Ghosh Dastidar and Prasun Banerjee.

The agency has also sought permission for prosecuting former MP Suvendu Adhikari who is currently transport minister in the Mamata Banerjee government in Bengal.

Mukul Roy, a former Trinamul leader now in the BJP, is also an accused in the case.

If the sanction is accorded, they may be named by the agency in its chargesheet which is likely to be filed soon, said an agency official.

The Narada sting case relates to politicians and bureaucrats who were taped while allegedly accepting money from a journalist posing as a representative of a private company.