Home Minister P Chidambaram met UPA Chairperson Sonia Gandhi on Monday evening. Finance Minister Pranab Mukherjee also called on the UPA Chairperson at her residence on Monday after his return from New York. Mr. Mukherjee said Home Minister was valuable colleague and a pillar of strength to the Government. The meeting comes in the backdrop of the issue over the Finance Ministry note on 2G Spectrum allocation.