Election 2019: Tejashwi Yadav said Rahul Gandhi shows "great maturity" in his style of leadership (PTI)

A coalition of progressive parties will come together to form the next government and Congress president Rahul Gandhi will play a "central role" in the formation of the new dispensation, RJD leader Tejashwi Yadav said on Thursday.

Asserting that the BJP has failed to deliver on its slogans, including ''achche din'', ''kala dhan vapsi (return of black money)'' and ''beti bachao beti padhao'', he alleged that the party has intensified its "hate-filled politics" to avoid being questioned on its promises.

Mr Yadav, whose Rashtriya Janata Dal is fighting the polls in Bihar in alliance with the Congress, Rashtriya Lok Samta Party, Hindustan Awam Morcha and Vikasshil Insan Party, also claimed the ''mahagathbandhan'' will sweep the polls in the state.

"Those who colluded in flouting people's mandate will be defeated. Uttar Pradesh and Bihar have always been key to forming central governments, that will not change," he told PTI in an interview.

"... I recognise that there is a strong anti-incumbency wave across India and each state will count," he said.

His remarks come ahead of the seventh and the final phase of the Lok Sabha polls on May 19 when polling will be held in eight constituencies in Bihar -- Nalanda, Patna Sahib, Pataliputra, Arrah, Buxar, Sasaram, Karakat and Jahanabad.

Mr Yadav, the younger son of RJD chief Lalu Yadav, also expressed confidence that a coalition of progressive parties will come together to form the government at the centre.

Asked if Mr Gandhi is the best bet among opposition leaders to lead the country as prime minister, Mr Yadav said the Congress chief has shown "great maturity" in his style of leadership.

"He mounted a very spirited and...a truly pan India criticism of the Narendra Modi government's policies. So yes, I feel he will be playing a central role in the formation of the new government," the former Bihar deputy chief minister said.

"Rahul ji is the president of India's oldest party, he has been a parliamentarian for the last 15 years, and five chief ministers are working under his able leadership. You tell me why he is not more suitable than the current PM," he asked.

At a rally in Samastipur last month, Mr Yadav also urged people to make Mr Gandhi the prime minister.

Asked if the RJD will back Mr Gandhi's name for prime minister if the opposition gets the required numbers, the RJD leader said, "I have been repeating it for months now. He (Gandhi) has been very consistent in providing an alternative vision of governance with ''Nyay'' (justice) and that is in sync with our core philosophy."

Mr Yadav also slammed the BJP for its narrative during the election campaign, alleging that in contrast to the 2014 polls when the promise of ''achche din'' was the BJP's plank, PM Modi has been grappling with various tropes but has not been able to rally the people around any one narrative.

"Anybody who is paying attention to social media in India today or has bothered to talk to the unemployed, daily wage poor, the middle-class salaried people, or the farmers, would know that the BJP, and PM Modi personally, have not been able deal with the anti-incumbency sentiments among these segments of Indian voters," he claimed.

The BJP put in efforts in intensifying its brand of "hate-filled politics" because it cannot afford to remind the electorate of the slogans around "achche din, kala dhan, beti bachao etc", the 29-year-old leader said.

Mr Yadav asserted that there is a wave against the Modi government and not an undercurrent.

"If a wave is not shown on television, does it become an undercurrent? History will judge the opposition mounted by the ''gathbandhan'' parties in the face of intimidatory tactics of the BJP -- the way they used state institutions to wage a war against the opposition and employed cheap tactics such as denying basic rights such as bail to popular leaders like Lalu Yadav ji," he said.

To a question on whether the results will surprise poll pundits, Mr Yadav said: "I'm sure the more experienced among them must be used to being surprised."

According to the seat-sharing arrangement among ''mahagathbandhan'' constituents in Bihar, the RJD was given 20 seats, out of which it gave one to CPI(ML) and the Congress is contesting on nine.

Upendra Kushwaha's Rashtriya Lok Samata Party is fighting on five seats with former Bihar chief minister Jitan Ram Manjhi's Hindustani Awam Morcha (HAM) and Mukesh Sahni's Vikassheel Insaan Party (VIP) contesting three seats each.

The ''mahagathbandhan'' in Bihar is up against the NDA. As per the seat sharing deal of the NDA, the JD(U) and the BJP are contesting 17 seats each, while Ram Vilas Paswan's Lok Janshakti Party is contesting the remaining six seats.