NEW DELHI: BJP on Tuesday demanded that Prime Minister Manmohan Singh be questioned by the CBI in the 2G spectrum case after former telecom minister A Raja told a court that every decision was allegedly taken with the PM's "concurrence".Describing Raja's deposition in the court as "shocking", BJP spokesperson Prakash Javadekar said, "Now CBI must interrogate the PM on 2G issues as the matter is in court and the probe will not be completed if PM is not interrogated. Now it is clear that PM is also involved in the scam."Raja, a key accused facing trial in the 2G spectrum case, had on Monday sought to drag Singh's name by saying that all actions were taken with the PM's "concurrence" and not "unilaterally".Javadekar said, "It is very serious revelation of former telecom minister A Raja in the CBI court. While answering thousands of questions he has made it very categorically clear that every decision about 2G was taken after PM okayed it."He said the PM owes an answer to the nation on the issue.Terming the UPA government as "most corrupt government that India has ever seen", the BJP leader also referred to the Commonwealth Games scam."Sunil Dutt, who was made chairman first, was replaced in a day by Suresh Kalmadi."Referring to the coal scam, Javadekar said, "As far as coal is concerned, the PM himself was the minister and every decision taken on coal mines has been done with his clear orders."The BJP spokesperson also condemned Priyanka Gandhi's "low-level politics" statement as "casteist""Congress is showing its real face now. In face of imminent defeat in Amethi they are unsettled. Therefore, Priyanka used bad language for Modiji saying "neech rajneeti" (low-level politics)."This is absolutely untenable. That is the way they are treating backward people. People have not forgotten how they had treated Sitaram Kesri and T Anjaiah. It is casteist politics," he charged.He said every abuse hurled by the Congress will turn into a complement for the BJP.Priyanka had hit out at Modi on Monday, saying he had insulted her "martyred" father Rajiv Gandhi during his speech in Amethi and accused BJP's Prime Ministerial candidate of indulging in "low-level politics".BJP also criticised TMC and Left, saying both have joined hands to defeat BJP in the elections."Today CPI leader AB Bardhan has said that to stop Modi we will support TMC. It is now clear that to vote for Left is to vote for Mamata Banerjee and vice versa because both are together now."He said their agenda is "negative" and it is a last ditch attempt by the Opposition to stop Modi from becoming the Prime Minister.Terming it as new "political polarisation", the BJP leader said, "Even the Left has joined hands with its traditional rival TMC. What Bardhan said has exposed Left politics. They were perceived to be against Mamata but now it seems their only priority is to stop Modiji in the face of support he is getting throughout the country."