Union Finance Minister Pranab Mukherjee has written a letter to Prime Minister Manmohan Singh to explain that he was not behind a controversial note on the telecom scam, which reportedly included an inference to a fellow minister P Chidambaram.

Mukherjee blamed senior officials at the Prime Minister's Office (PMO) and the Cabinet Secretariat for officially circulating the 2G note. The note questioned the role of then finance minister P. Chidambaram in the spectrum allocation.

The letter from September said that the Department of Economic Affairs was against sending the note and he affirmed that the note was sent after instance from the joint secretary at the PMO. He pointed out that the note would not have come into the public domain through the RTI act if it was not formalized.

The note in question has caused a huge controversy and even gave a reason to opposition parties to demand Chidambaram's resignation from the post of Home Minister and explain his involvement in the case.

The Prime Minister has publicly defended Chidambaram but the BJP insisted on the home minister's resignation. Sonia Gandhi had to intervene in the matter.