Taking a serious View of the fiasco in the appointment of the chief vigilance commissioner, the Congress core committee is understood to have directed prime minister Manmohan Singh to revamp the prime minister's office (PMO) since the existing officers appear to be misleading him.

Sources said Congress president Sonia Gandhi put a question mark on the PMO in the core committee meeting Thursday night, pointing out that she has been told that it was the PMO that repeatedly insisted on making P J Thomas as the CVC.

She asked the PM to identify the officers in the PMO who were pushing for Thomas and pointed out that their role in the ISRO spectrum controversy as also issues concerning the 2G scam should also be probed as their wrong advice has been putting the party into difficulties, the sources said.

Two select ministers who attended the meeting also confirmed on Friday that Sonia Gandhi conveyed her anguish over the negative publicity for the past six months because of the selection of Thomas.

The sources said the needle of suspicion falls on the PM's secretary T K A Nair, a retired Punjab cadre IAS officer with Dr Manmohan Singh since 2004, as he was one who got the name of Thomas included in the panel of names shortlisted for the post.

They said it was again Nair who had assured the PM that Thomas was an officer of impeccable integrity and cited the views he had gathered in this regard from a score of bureaucrats from Kerala who had worked with the ousted CVC.

Since Thomas had been the chief secretary of Kerala, sources said the PM had also consulted defence minister A K Anthony who also described him as an upright and honest officer. They said Dr Manmohan Singh told the core group meeting that he had gone by the advice given by Anthony and his officers in the PMO and did not expect appointment of a fine officer like Thomas will put the government into difficulties.