New Delhi, May 6 -- The Supreme Court on Monday sought a response from the Centre on a petition seeking quashing of an order blocking a YouTube channel, 4PM, citing "national security" and "public order". The plea said that the blocking order was effected by the intermediary, in this case YouTube, following an undisclosed direction from the Centre. A bench of justices BR Gavai and KV Viswanathan agreed to hear the plea and issued notices to the Centre and others seeking their responses. The plea, filed by Sanjay Sharma who is the editor of digital news platform "4PM" with 7.3 million subscribers, has alleged that the blocking was a "chilling assault on journalistic independence" and the right of public to receive information. Senior advocate Kapil Sibal, appearing for the petitioner, said, "This is ex-facie unconstitutional. I have not been served a copy of the blocking order. Only information I have is from the intermediary." The plea, filed through advocate Talha Abdul Rahman, said no blocking order or underlying complaint was furnished to the petitioner, violating both statutory and constitutional safeguards. "National security and public order are not talismanic invocations to insulate executive action from scrutiny," the plea said....