many say - the real centre of power in India.

Sonia underwent treatment overseas last year, reportedly for cancer, and while she has resumed party duties there are doubts about how long she can maintain the pace.

Given the risk of a leadership vacuum, it may soon be now-or-never time for her son. But since 2004 when he first joined parliament, Gandhi has focused much of his political energy on Uttar Pradesh, which with 200 million people would be the world's fifth-most populous country if independent.

It sends 80 members to the 543 elected parliamentary seats in New Delhi, making control of the state crucial to run the federal government.

The family is notoriously shy of the media and Gandhi did not respond to requests for an interview. But aides say he sees Uttar Pradesh as a microcosm of India and chafes at the fact that the state government is headed by an opposition party.

"He and his family belong to the state, and that is something the whole nation is aware of," said Minister of State for Telecommunications and IT Sachin Pilot, who is often mentioned in the local press as part of Gandhi's "brigade".

"There is a need not just for a change in political leadership but more importantly to bring about a transformation in the lives of the people. That is a much more compelling theme behind his actions as opposed to just grabbing of power."

Indeed, Gandhi seems much more comfortable on the stump in the dusty plains of Uttar Pradesh than he is in parliament.

In Bhakurai, a village 5km (3 miles) down a dirt-track off a state highway, more than 10,000 people gathered recently amid wheat and mustard fields to hear him speak, and cheered when he waved at them with a broad smile.

"I have learned more from you in these seven years than I ever could have studying in America and Britain," he said in the sing-song Hindi dialect of the region.

"Arrey bhaiyya (Hey, brother) I haven't come to win an election, I have come here to help Uttar Pradesh stand up for itself."

"The elephant," he said, referring to the election symbol of the Bahujan Samaj Party (BSP) that rules the state, "is eating money. I have heard of an elephant eating grass, but this one eats money.

"The cycle has got punctured," he said referring to the symbol of another rival party.

The similes go down well with the crowd.

"There will be change this time," said Ramesh Tiwari, a middle-aged man watching Gandhi speaking from a rickety wooden stage festooned in Congress' orange, white and green colours. Tiwari said he and many others had cycled over 10km (6 miles) to hear Gandhi speak. Some, he conceded, had come to see the helicopter that would whisk him away but, he added: "He is talking sense. He knows what he is saying."

Not the nation's favourite
Congress has not won a state election in Uttar Pradesh for 22 years, which largely explains its inability to take power on its own in New Delhi. It has won the last two federal elections with coalition governments, which have left it vulnerable to demands for cabinet posts and policy compromises. And it is seen losing ground.

An opinion poll by the India Today weekly said that Congress would win only about 110 seats in Parliament if national elections were held now, its lowest tally ever and against the 206 it won at the last elections.

"There is clear public dissatisfaction over the manner in which the government has responded to charges of corruption," the magazine said.

"The government's economic mismanagement, reflected in stalling growth and persistent inflation, is also taking a toll on its electoral fortunes."

Gandhi's slowly-slowly strategy and his decision to stake so much on Uttar Pradesh could go horribly wrong if Congress fails to make a good showing in the state assembly elections and at least become part of a coalition government there.

Nationwide, the India Today poll had Gandhi favoured by only 17% of respondents to be the next prime minister, bested by 24% for Narendra Modi of the opposition Bharatiya Janata Party (BJP) who has an image as a hardline Hindu leader.

It doesn't help that Gandhi has not made much of a mark in parliament in his seven years as a lawmaker. His speeches have been lacklustre, he rarely initiates debate and a much-awaited statement when the country was riveted by a hunger-striking anti-graft campaigner last year did not rise above the mundane.

"We still have an inadequate understanding of him to form an opinion," said Arun Jaitley, leader of the opposition BJP in the upper house of parliament.

"Unless people interact beyond a point with different sections of society and are open for grilling and questioning, their real worth is not known. Politics is a lot more than merely photo opportunities.

"I have just heard him making some unilateral statements and those statements have pedestrian sentences like 'We give money to the states and the states don't spend them' and 'I want youth to get into politics'."

India's Kennedys

No one in the family has been as good an orator as Jawaharlal Nehru, India's first prime minister. Still, they are perhaps the only politicians whose appeal cuts across caste and religious lines, which decide most elections in the country.

The political lineage, likened to the Kennedys in the United States both for the power it has enjoyed and the tragedies that have befallen it, started with Motilal Nehru, a Brahmin from Kashmir who practised law in Uttar Pradesh in the early 20th century and gave up a Western lifestyle to become president of the Congress party.

His son, Jawaharlal, was independence hero Mahatma Gandhi's closest confidante and prime minister from 1947 until 1964.

Jawaharlal's daughter, Indira, married a Gandhi who was no relation to the Mahatma, but the name was certainly no handicap in politics.

Indira became prime minister in 1966, but was voted out in 1977 after imposing a harsh internal emergency on the country, becoming the first of her family to lose a national election.

But the mystique of the dynasty brought her back to power within three years and her son Rajiv took over after she was shot dead by two bodyguards in 1984.

Rajiv Gandhi served one term as prime minister and when he was campaigning for a comeback in 1991, he was assassinated by a suicide bomber.

Those killings have made Rahul, his mother Sonia and sister Priyanka among the most protected people in the world.

Armed men in suits and dark glasses guard them at public functions and, for security reasons, Rahul even used a false name at university and when he worked in London at the turn of the century. But the family tries to balance the security constraints with campaigning and regular public appearances.

Big gamble on state election
Sonia, who took over the presidency of the Congress some years after her husband's death but refused to become prime minister, gets much respect in public, for eschewing office, her faultless Hindi and conservative Indian dress and also for staying on despite the tragedies.

Priyanka Gandhi attracts large crowds when she campaigns for her brother, partly because of her uncanny resemblance to her grandmother, Indira, but she is staying away from a wider role.

In the end, what Rahul Gandhi does or is able to do will be decided by the Uttar Pradesh elections. A poor performance by Congress may embolden the opposition and force an early general election; a good showing will give the party more space to put its house in order and allow Gandhi to take his time.

"The Uttar Pradesh election result is very pivotal," said Parliamentary Affairs Minister Rajeev Shukla, who is close to the Gandhis.

The Congress party won a miserable 22 seats out of 403 in the state's last polls. If this is increased to even 80, Gandhi would have succeeded, since his party would be in a position to join a coalition government.

However, party insiders dismissed suggestions that Gandhi might take a role in the Uttar Pradesh administration: they would much rather he become prime minister.

"My vote is he's up to it and he should take on the role as soon as possible depending on what timing he is comfortable with," said Pilot, the communications minister.

"As far as I see it, he has all that it takes to lead from the front. But he is not thinking of power - that's not a priority."

—Additional reporting by Annie Banerji; Editing by John Chalmers and Neil Fullic