A preliminary inquiry conducted into the alleged blacking out of the first few minutes of Trinamool Congress leader Derek O'Brien's speech by Rajya Sabha Television has found that power failure was responsible for the four-minute break in transmission.

However, Rajya Sabha Chairman M Venkaiah Naidu has ordered a detailed inquiry into the matter, Rajya Sabha was informed today.

O'Brien had raised the issue in the Upper House on February 7, saying "I seek your protection.. I spoke today in Rajya Sabha. The first 4-6 minutes of my speech were not shown on Rajya Sabha TV. I am a member of the Opposition. You protect us".

Leader of Opposition Ghulam Nabi Azad had dubbed it as a "very serious issue" and said "don't convert Rajya Sabha TV into BJP TV."

BJP leader Satyanarayan Jatiya, who was in the Chair then, had assured a probe in the matter.

Making a statement in the Upper House today, senior BJP member Basawaraj Patil, who was in the Chair, said "an inquiry was conducted and it was found that there was a break in the live transmission of Rajya Sabha TV from 13:14 hours to 13:18 hours, four minutes when Derek O' Brien was speaking due to power failure."

Patil said that after the transmission resumed, the incident was regretted by the Rajya Sabha TV through a scroll.

It also flashed that the entire speech of O'Brien would be telecast in the evening at 20:15. hours.

"The Chairman (M Venkaiah Naidu) has however ordered a detailed inquiry into the matter," Patil informed the members.