With the Left deciding to snap ties with the United Progressive Alliance, President Pratibha Patil [Images] will face her first real test on whether to ask Prime Minister Manmohan Singh [Images] to seek a trust vote in Parliament or not.

Patil, 72, will find herself in the spotlight at the end of a fortnight-long political manoeuvering and intense speculation on whether the Manmohan Singh government will have the numbers to survive a floor test.

Constitutional experts say Patil has two options before her -- either to ask the government to prove its majority or go by the letter of support given by Samajwadi Party and others in 2004, a precedent set by President K R Narayanan.

"The President should ask the government to prove its majority in the floor of the House since there is news emerging that some Samajwadi Party Members of Parliament are against the deal and would vote against the deal even if the party issues a whip. In light of this, the President is left with no option but to ask the government to prove its majority," senior advocate Raju Ramachandran told PTI.

However, former Law Minister Shanti Bhushan said there was "no point in the Constitution which talks about confidence motion for a functioning government" and hence Patil was not required to ask the government to prove its majority.

"Confidence motion is moved in the Parliament in case of newly formed government. It is for the opposition to do so and not the President," he said.

Bhushan's view is also supported by senior advocate KTS Tulsi, who says that the government does not even need a formal letter of support from the Samajwadi Party at the moment.

"It is wrong to assume that the government is in minority. The government also does not require any formal letter of support from the SP since no new government is being formed," he said.

Earlier, after the 1998 general elections, the then President Narayanan faced a unique situation with Atal Bihari Vajpayee staking claim to form the government since the Bharatiya Janata Party had emerged as the single largest party leading the pre-election coalition -- the National Democratic Alliance -- even though he did not have a majority.

Narayanan had then asked Vajpayee to furnish letters of support to demonstrate NDA's ability to secure a majority.

Vajpayee, who was able to meet the demand, was then appointed the Prime Minister (March 15, 1998) on the condition that the vote of confidence should be secured in 10 days.