new delhi an angry congress on wednesday demanded that prime minister narendra modi apologise for his ugly remark against former premier manmohan singh or else it would not let the rajya sabha function after walking out of the house in protest deputy leader of opposition anand sharma p chidambaram and kapil sibal condemned modis attack on singh as most unacceptable it is in extremely poor taste it is unbecoming of a pm to use such language for a former pm and certainly unbecoming for anybody to make such a harsh ugly statement about manmohan singh chidambaram said the former finance minister said congress was very very angry over the remark and could have shouted down the pm during his reply to the presidents address but that would have in the circumstances of today brought us down to the level of the debate which the pm wanted we do not want such a debate to take place he said the congress threat of blockade threatens to revert parliament back to the chaos of the winter session but for the moment it may hurt business only on thursday after which the two houses go into a monthlong break calling the pm unprecedentedly arrogant sibal said modi had conveyed that he would not come to the house for his reply till deputy leader of opposition anand sharma had finished his speechhe should know he is everybodys pm including ours the post he occupies has dignity he said watch cong slams pm modi for ugly remark against manmohan singh seeks apology