Accusing the Congress of indulging in 'trade-off' with the Samajwadi Party for the government's survival, the Bharatiya Janata Party on Saturday asked Prime Minister Manmohan Singh [Images] to immediately seek a vote of confidence in Parliament.

"The government has been reduced to a charade. It has lost the moral legitimacy to govern. For survival, the government seems ready to trade off anything," BJP's Prime Ministerial candidate L K Advani told a crowded press conference in New Delhi.

He demanded that a special session of parliament should be convened and Dr Singh should prove his majority on the floor of the House once the Left parties withdraw support.

"Credibility of the Congress and Samajwadi Party lies in shambles," the senior BJP leader said, a day after the Congress clinched a deal for getting the support of the SP, which has 39 members in Lok Sabha, in the event of a confidence vote.

Congress wooed the SP after it became clear that Left parties, which have 59 members in the Lok Sabha, would snap ties with the United Progressive Alliance if the government went ahead with the Indo-US nuclear deal.

Differences between the two principal partners of the UPA has paralysed the government for the past 18 months," Advani said, referring to the stand-off between the government and the Left parties on the nuclear deal.

On the Samajwadi Party announcing its support for the nuclear deal, Advani said it was surprising to see 'two bitter enemies' became allies in a matter of a week.

The impasse over the nuclear deal has led to a realignment of political forces at the Centre, with the Congress clinching a deal with the SP, which will extend outside support to the UPA government, as the Left parties are all set to sever ties with the ruling alliance.

Advani admitted that the Bharatiya Janata Party government, if elected to power, would like to renegotiate the nuclear deal, but added, " it would have to be done on equal footing. The UPA has consented to agreeing to this deal at a place dictated by the United States, and at their convenience. To keep the US establishment happy, propriety, the principles of governance, and probity in public life have been abandoned."

He refused to comment on whether Lok Sabha Speaker Somnath Chatterjee should also resign from his post if the Left parties withdrew their support from the UPA coalition. "I do not want to comment on it. It is for the individual and the party to decide," he said.

 "The government has neither the requisite majority nor the moral authority to trade the future of many generations of Indians," Advani thundered.

"After the People's Democratic Party withdrew support from the Gulam Nabi Azad-led government in Jammu and Kashmir [Images], the governor asked Azad to prove his majority before July 7. Dr Singh should do the same. The prime minister and the Congress must explain the reasons which compel them to rush the country into this agreement, in such desperate haste," he added.