Lok Sabha speaker Om Birla on Friday said that the Opposition parties should have participated in the function of the Constitution Day as it was a function of Parliament not of the government.""Constitution Day" function was of Parliament and not of government. I am upset by the boycott of Opposition parties. It is my endeavour that there should be no tradition of a boycott during the address of President, Vice President, and the Governor," Mr Birla said.Several Opposition parties including Congress boycotted the Constitution Day celebrations today at Central Hall of Parliament.The Lok Sabha Speaker added that he had also said this in the presiding officers' conference that if anyone has any complaint or issue, then he can talk to me. "There may be disagreement. But, let us carry on the good tradition.""There were arrangements made for both Leader of Opposition in Rajya Sabha, Mallikarjun Kharge and Leader of the Congress party in Lok Sabha Adhir Ranjan Chowdhury to sit on the dais. They were informed about the same by the Parliamentary Affairs Minister and my office. Still, they did not come and said that there is were no seating arrangements on the dais. This is wrong," Birla said.Several Opposition parties including Congress, Left parties, All India Trinamool Congress (TMC), Rashtriya Janata Dal (RJD), Shiv Sena, Nationalist Congress Party (NCP), Samajwadi Party (SP) boycotted the Constitution Day.President Ram Nath Kovind led the celebrations of Constitution Day at the Central Hall of Parliament House onwards on Friday.The nation celebrates Constitution Day on November 26 to commemorate the adoption of the Constitution of India by the Constituent Assembly in 1949.The observation of Constitution Day started in 2015, based on the vision of the Prime Minister to give due recognition to the significance of this historic date.The roots of this vision can also be traced back to the "Samvidhan Gaurav Yatra" organised by the then Gujarat Chief Minister Narendra Modi in 2010.