Following the breakup of the saffron alliance, the Shiv Sena has taken an increasingly strident sons-of-the-soil position, that may result in a consolidation of non-Maharashtrian voters behind the BJP. And it appears that the party will look to sharpen this division, particularly in the Mumbai and Thane region.

The focus has been particularly on the Gujaratis, which is not surprising, as both Narendra Modi and Amit Shah, who have together scripted the BJP's Maharashtra assembly campaign, are from Gujarat. And they are seen as being responsible for the split in the 25-year-old alliance.

The Sena, through its mouthpiece Saamna, has accused the BJP of trying to break up the state, carving out a separate Vidarbha, at the behest of 'seth sahukars' (money bags) and that it wanted to also sever Mumbai from the state.

A couple of days ago, it asked how Modi could promise to develop Maharashtra when Anandiben Patel, the BJP's CM in Gujarat, was wooing Maharashtra's industrialists to move to her state.

A Sena candidate from the city agreed there was a Maharashtrian undercurrent, but explained that it was the result of an increasing assertiveness among Gujaratis since Modi became PM. Now, Sena supporters suggest that the attack has led Shah to go slow on campaigning.

Surendra Jondhale, professor, department of civics and politics, University of Mumbai, said Uddhav Thackeray could seek to polarise Marathi voters as the BJP is seen as a party of traders, upper castes and non-Maharashtrians. "It may also be necessary for him to check the advance of the Maharashtra Navnirman Sena (MNS)," he said.

For the record, though, the party has nominated Gujaratis and a North Indian among its candidates in Mumbai.

In fact, Raj Thackeray, whose MNS has agitated against the influx of outsiders to Mumbai, has ramped up criticism of Modi for focusing excessively on Gujarat and reminding him that he is PM of India.

The animosity is not new and dates back to the days of the reorganisation of Bombay state, after a bloody movement in which 105 people were killed.

Then in 1969, the Sena came out on the streets for the first time, over the border dispute with Karnataka. Morarji Desai – also a Gujarati – was deputy prime minister and they sought to submit a memorandum to him after a clash with the police. But Bal Thackeray was arrested together with Manohar Joshi and Datta Salvi and jailed at Yerawada.

However, a former Sena MLA admitted that the polarisation could also work against the party as the number of non-Maharashtrian voters has increased significantly even in traditional Maharashtrian strongholds.

"Moreover, all Maharashtrians are not with the Sena. Some are with other parties and a section of Maharashtrian upper caste voters may even prefer the BJP," he said.

This change has also bolstered the Gujaratis. "The Shiv Sena is struggling to make its presence felt in the city. The Marathi votes are divided, which is why it is targeting Gujaratis in an attempt to try and consolidate the Marathi voters. But they will not get anything," said a prominent Gujarati leader.

A prominent Maharashtrian leader in the BJP says much has changed since Bal Thackeray passed away. "Those days are gone when about 50 sainiks would take charge of an area, ensuring to do the work assigned to then by Balasaheb. They didn't fear going to jail and didn't have to bother about their future. Now educated Marathi youth are smarter and the Sena finds it difficult to mobilise them for protests or rallies," he said.