BJP MP Babul Supriyo broke with tradition on Sunday evening as he refused to congratulate the ruling Trinamool Congress on an emphatic win in the 2021 Bengal Assembly election.
In a short but angry Facebook post Mr Supriyo said the Bengali voters had made a "historic mistake" and lashed out at party chief Mamata Banerjee, whom he labelled a "cruel lady".
"Neither will I congratulate Mamata Banerjee... nor do I wish to say I 'respect' the people's verdict... sincerely think people of Bengal made a historic mistake by not giving BJP a chance... by electing this corrupt, incapable, dishonest government and a cruel lady back to power," he ranted.
"Yes, as a law-abiding citizen, I shall 'obey' the decision taken by the people in a democratic country... That's it !! Nothing more - Nothing less !!" Mr Supriyo declared.
The post was later deleted.
Mr Supriyo's colleagues, though, including Prime Minister Narendra Modi, have been more gracious.
The Prime Minister congratulated Ms Banerjee and said the centre will "continue to extend all possible support to... fulfil people's aspirations... and also to overcome the COVID-19 pandemic".
Congratulations to Mamata Didi for @AITCofficial's win in West Bengal. The Centre will continue to extend all possible support to the West Bengal Government to fulfil people's aspirations and also to overcome the COVID-19 pandemic. @MamataOfficial— Narendra Modi (@narendramodi) May 2, 2021
"Congratulations to the Chief Minister of West Bengal, Mamata Banerjee on her party's victory in West Bengal assembly elections. My best wishes to her for her next tenure," Mr Singh said.
Congratulations to the Chief Minister of West Bengal, @MamataOfficial Didi on her party's victory in West Bengal assembly elections. My best wishes to her for her next tenure.— Rajnath Singh (@rajnathsingh) May 2, 2021
Congratulations Mamata Banerjee and All India Trinamool Congress (on) being elected again in the Assembly election. Good wishes for your next tenure," Ms Sitharaman tweeted.
In his own fight, Mr Supriyo - one of four MPs roped in by the BJP, in an unusual move, to contest in a state election - lost to the Trinamool's Aroop Biswas from Tollyganj by over 50,000 votes.
The Trinamool is en route to a dominant win, with the latest trends showing it will win 210+ seats to the BJP's 80-odd. The victory is all the more surprising given how tight the race was expected to be.
The win, though, has been marred by news that Ms Banerjee has lost to the BJP's Suvendu Adhikari, her former right-hand man; the two were locked in a high-stakes prestige battle from Nandigram.
In her initial remarks Ms Banerjee has played down the significance of her loss, arguing that it is more important for the Trinamool to win than any one person.