Voicing concern over the challenge posed by proponents of extremist ideologies through intimidation and terror, the Prime Minister has called for effective steps to tackle this grave menace. Dr Manmohan Singh said, the growth of extremist ideologies is threatening civilised existence. He said, the proponents of such ideologies are challenging the tenets of democracy by resorting to intimidation, terror and other manifestations of intolerance. Dr Singh said this while inaugurating a Conference of Speakers and Presiding Officers of the Commonwealth in New Delhi on Tuesday. He said one should not and cannot give any quarter to such forces and all should look at ways and means by which such forces can be eliminated without undermining the democratic foundations. In her welcome address, Lok Sabha Speaker Mrs Meira Kumar said, India is the largest working democracy in the world and its Parliament has acquired pre-eminence in the political system. The Conference is being attended by 50 Speakers and Presiding Officers of 42 Parliaments in Commonwealth countries, including Pakistan.