The fight between two factions of the Trinamool Congress reached Nirvachan Sadan on Thursday, setting the stage for a formal split as the breakaway lobby in the Assembly claimed the party name, the twin-flower symbol and the funds.

The leader of the Opposition, Ritabrata Banerjee, who leads the rebel faction in the House, met chief election commissioner (CEC) Gyanesh Kumar and other members of the Election Commission (EC) to make the claims.

At simultaneous news conferences in Calcutta and New Delhi, Trinamool's Mamata Banerjee-led Kalighat camp accused Union home minister Amit Shah of running the EC through "his appointed crook", Kumar, to orchestrate the meeting.

Ritabrata, flanked by the rebel bloc's designated Trinamool chairperson Arup Roy and eight others, said: "We are mango people, not chartered people."

He deployed a pun on "aam" — which, in the word from Arabic roots means "common", and in the one from Sanskrit roots means "mango" — to set themselves apart from the Abhishek Banerjee brand of the party.

"Out of every ₹4 spent by the party, ₹1 was spent on chartered flights.... There is a mafia that has developed, similar to the one in Germany in the 1930s. A chartered mafia and bureaucrats who had taken control of our grassroots party that has fallen like a house of cards," Ritabrata added.

Sources in his bloc said they staked a claim on everything from the name and the symbol to the funds.

Without naming Mamata's nephew Abhishek, Ritabrata targeted him in the bloc's war against the "cult of the individual, dictatorship, and dynastic politics". He underscored that a special session convened at a New Town hotel on June 22 had systematically purged both the aunt and the nephew to form a new national working committee, installing Roy as chairperson.

An EC official told The Telegraph: "We will now write to the party that is registered with us and ask them if they agree to these changes that have been brought to our notice by the delegation that came here today. If they reply to us saying that they disagree with these changes, then the EC will formally issue a 'Declaration of Dispute' and initiate proceedings as per law."

"The EC has written letters to both Mamata Banerjee and Ritabrata Banerjee regarding the claims and counter-claims by both factions with respect to organisational elections/authorised signatories of the Trinamool Congress. They have been asked to submit their responses by 5.30pm on Monday (July 6)," an EC spokesperson said late in the evening.

For adjudicating upon a dispute within a party as described under Para 15 of the Symbols Order, 1968, the poll panel adheres to the tests laid down by the Supreme Court in Sadiq Ali versus the EC, 1972. These are the tests of aims and objects, party constitution and majority.

In the case of the Shiv Sena, the EC relied on the test of majority because it observed the undivided Sena did not provide the list of office-bearers whenever they were elected, and had amended its party constitution to undo democratic norms introduced in 1999 at Nirvachan Sadan’s prodding. This made the “party akin to a fiefdom".

The Eknath Shinde group of the Shiv Sena proved that it enjoyed the support of 40 out of 55 MLAs, and 13 out of 22 MPs. Uddhav Thackeray’s faction was supported by 15 MLAs, all 12 MLCs, and seven MPs.

The NCP met a similar fate, while the Lok Janshakti Party was split down the middle, with neither faction getting the name or symbol of the original party.

In Trinamool's case, Ritabrata claims the support of at least 64 of 80 MLAs. But Trinamool's 20 Lok Sabha members have broken away to join the Nationalist Citizens Party of India. Of Trinamool's 13 Rajya Sabha members, four have resigned, with more to follow soon.

"The Trinamool case is unique on multiple counts, as there are three different need-specific models for three different Houses, although all three blocs are on the same page. And Kalighat is in a different book," a Trinamool old-timer told this newspaper.

He said while the Assembly bloc promised "constructive Opposition" but not "Opposition for opposition's sake", the Lok Sabha bloc has publicly aligned itself with the NDA under Narendra Modi's leadership. He added that those resigning from the Rajya Sabha were promised either re-election as BJP nominees or other rewards for giving up their seat.

"That is why this is not the Shinde or the (Raghav) Chadha model. It is the Ritabrata model in the Assembly, the Kakoli (Ghosh Dastidar) model in the Lok Sabha, and the Sukhendu (Sekhar Ray) model in the Rajya Sabha. This level of nuanced ingenuity is peerless," the source said.

In Delhi, Mamata loyalists and MPs, Sagarika Ghose and Saugata Roy, labelled the Ritabrata bloc's visit to the EC headquarters "illegal", noting that EC guidelines strictly state only authorised representatives can meet the full bench.

"We decide who represents our party," said Saugata.

"Gyanesh Kumar is the first CEC to have faced a removal proceeding in Parliament. That says volumes about his lack of integrity," he added. "Today's meeting is being held by Amit Shah's appointed crook at his (Shah's) behest."

In Calcutta, Mamata loyalist and MLA Kunal Ghosh dismissed the Ritabrata bloc's claims to legitimacy.

"Those claiming to be "ashol" — the affidavit they submitted for contesting elections to the commission two months ago had the signatures of Mamata and Abhishek on two specific forms. The tenant claims to be the landlord now," he said.

The rebel camp remains unmoved by the tenant analogy, digging in for a protracted administrative war.

"Why should we demand the symbol or anything else?" asked Ritabrata. "Two-thirds of the MLAs are with us. We are Trinamool."