"Good times are coming," he often says, to rapturous applause.

But don't be fooled: all is not well at home.

Humiliating defeats

There's a growing sense in India that Modi's campaign speeches have been high on promises but short on delivery and implementation. Despite personally campaigning in elections in the states of Delhi and Bihar this year -- rare for a sitting Prime Minister -- Modi's Bharatiya Janata Party (BJP) suffered humiliating defeats.

Critics within Modi's own party say their leader has developed a near-authoritarian style of management, concentrating power at the very top between himself and a few key aides. Modi's opposition has an even easier line of criticism: we told you so.

There's an eerie predictability to Modi's current problems. In his previous role as Chief Minister of the state of Gujarat, Modi was long seen as being a Chinese or Singaporean-style leader, with free-reign to make big-ticket decisions without public consultation.

READ: How was Modi's first year?

Even more worrying has been the use of religion on the campaign trail. Modi has history here. In 2002, under Modi's rule, the state of Gujarat saw some of the ugliest scenes in living memory: more than 2,000 Muslims were murdered, raped, or burned alive by their Hindu neighbors in what Human Rights Watch says was a planned attack.

Modi's critics say he was complicit, but he was cleared by the Supreme Court. Even if Modi had absolutely no knowledge or role in the riots, his reported response has been much cited: that his only regret was that he could have managed the media fallout better. Either way, the offshoot of the riots was Modi cementing his reputation as a lion amongst Hindus, a no-nonsense strongman who protected his own.

Faustian pact

When Modi was elected Prime Minister in 2014 -- in large part because of his inspirational promises to bring development and high speed growth to India -- the country hadn't forgotten about the 2002 riots. Even amid the euphoria there was an uneasy sense of a sort of Faustian pact, that secularism could be forgotten for a while if development was delivered.

But growth and reforms, while evident, have been slower than promised. And the ugliness of baiting Hindus against Muslims has been exposed in an ugly spotlight.

In recent weeks as many as four Muslims have been killed on suspicion of consuming or transporting beef. Modi's supporters will say this has nothing to do with their leader;

Modi's critics will say that when the Prime Minister says his opposition wants a "pink revolution" -- a reference to cow flesh -- then he's emboldening people who equate India with Hindus, and Hinduism with not eating beef.

Neither correlation works -- in a region filled with religious extremism, India was meant to be a beacon-like example with a constitution that enshrined secularism and choice.

In allowing his critics to say 'I told you so' Modi has lost a golden opportunity in the form of a rare parliamentary majority. In two consecutive state elections, India's electorate—always smarter than it is given credit for—has given Modi a clear message that he needs to listen and change.

Despite his recent missteps, and you can read more about them here, Modi remains the country's most popular politician. Modi remains a powerful leader with a strong national mandate. And he has good ideas to make business more efficient, to attract foreign investment, and to digitize India's bureaucracy.

But as tens of thousands chant his name at London's Wembley stadium, it's worth keeping in mind that back at home, the man and his aura have dimmed.

Modi, the rock star needs to change his tune.