But, in his first press conference in India in more than three years, Dr Singh’s refusal to announce that Rahul Gandhi will lead the Congress Party to elections in May, was emblematic of much that has beleaguered his premiership.

Mr Singh wanted to announce the man he would have succeed him – he said Mr Gandhi had “outstanding credentials” - but it was not his place, nor his prerogative to do so. Ostensibly the leader of the world’s largest democracy, he still had masters to answer to.

“The party will announce a prime ministerial candidate at the appropriate time,” he said.

For nearly 10 years, one of India’s most brilliant men and a key architect of its modern economy has been, to this nation’s detriment, a prime minister without power.

Speaking to reporters on Friday, Dr Singh outlined the achievements of his government, stressing efforts in poverty reduction and improvements in the lives of women, food security and education.

But even his efforts to sell his government’s decade in office struck a defeatist tone, as though the election had already been lost.

“Our government will work ceaselessly until its final day. Jai Hind [long live India,” he said.

Dr Singh has never been a comfortable media performer – part of the reason he so rarely speaks to reporters. His reputation is instead built on his economic management, and the modernising reforms he championed in the 1990s.

While his first term in office was lauded for its unprecedented economic growth, his second, beginning in 2009, has been marred by successive corruption scandals.

Dr Singh is seen as a dedicated public servant and scrupulously honest, but also as a man put in charge of a deeply corrupt government he is powerless to control.

As Prime Minister, Dr Singh has been constricted. The unspoken power-sharing arrangement with Congress president Sonia Gandhi – the real centre of power in India – has made him appear uncertain, even timid.

Asked again who would replace him as the Congress candidate for prime minister, he answered: “The Congress president has already answered that question. We will announce our candidate … at an appropriate time.”

There were occasional signs of fight from the PM.

Asked if he thought he was a weak leader, as his detractors have alleged, Dr Singh attacked the leader of the opposition BJP, the controversial Narendra Modi, who he said would be “disastrous” as prime minister.

“I don’t think I have been a weak PM. But if strength means that I preside over the brutal massacre of innocent people on the streets of Ahmedabad, I do not believe that is the kind of strength that India needs, least of all in its prime minister," he said.

He was referring to Mr Modi’s role in the anti-Muslim riots that seized his state in 2002 and resulted in at least 1000 people killed. Mr Modi was accused of encouraging the religious violence, or at least of not acting to stop it. He has always denied any wrongdoing.

Generally, Dr Singh confirmed the impression of a prime minister who had little, if any, power over a corrupt, even criminal, cabinet.

He lamented two of his government’s largest corruption scandals – coal block allocations and telecommunications licences – saying he had argued for more transparent governance.

“I feel somewhat sad as I was the one who insisted that the [mobile phone] spectrum allocation should be fair, transparent and equitable,'' he said. ''I was the one who insisted that coal blocks should be allocated on the basis of auctions.”

His public performance on Friday could not have contrasted more sharply with the recent appearances of the man who will lead the opposition BJP to the polls.

Narendra Modi is a bombastic and aggressive public speaker. Always on message to his Hindu nationalist heartland, he almost never speaks English.

Dr Singh is quiet, and unassuming, a reflection of the university lecturer he once was. Even when questions were to put to him in Hindi on Friday, he chose to respond to in English.

But while Dr Singh came to the prime ministership widely respected for his handling of India’s economy as finance minister, Mr Modi is a hugely polarising figure across the country.

His supporters point to the ‘'self-made man’' narrative he promotes, and his economic stewardship of Gujarat, where he has been Chief Minister for more than a decade. But his critics point to his dictatorial and autocratic style, and his repression of political opposition.

At the moment, Mr Modi and the BJP have the ascendancy over Congress. Rahul Gandhi will be the next prime ministerial candidate for Congress, everybody in India knows it. But the party continues to dither about announcing it, giving the scion of India’s first family precious little time to establish himself.

Meanwhile, Mr Modi looks more and more prime ministerial every day.