The Trinamul Congress came out firing on all cylinders on Monday, sustaining pressure and building momentum through the day, in taking on the “politically motivated” Narada-related hyperactivity of the CBI — backed fiercely by the saffron ecosystem — thinking it was ending the day on a note of triumph, but the euphoria was shortlived.

The lower court’s interim bail, granted in the evening to Trinamul heavyweights Subrata Mukherjee, Firhad Hakim, and Madan Mitra, besides former Trinamul leader Sovan Chatterjee, who quit the BJP just before the elections, was stayed late at night by Calcutta High Court. The matter was fixed for hearing by the high court on Wednesday, till which time the four leaders are to stay in judicial custody.

Trinamul’s lawyer-MP Kalyan Banerjee, who spearheaded the legal proceedings on behalf of the party, said at night that the high court developments were “unheard of” and he needed more time to understand what actually had happened there.

Sources in his party, on the condition of anonymity, attributed to the Serampore MP’s “over-confidence” some of the blame for the setback.

Earlier in the day, Trinamul chief Mamata Banerjee had led from the front with a defiant six-hour stay at the CBI office in the Nizam Palace, resisting the browbeating attempts by the bellicose Union home ministry under Amit Shah that the central agency reports to.

The CBI and its political masters, who seemingly had otherwise planned for the sequence of events of Monday morning rather meticulously, found themselves in a corner when the chief minister walked in around 10.50am and demanded that she, too, be arrested, along with her party colleagues whom they had picked up earlier in the morning.

“That’s when she (Mamata) began forcing them on the backfoot. They had factored in a dharna elsewhere, like on the Rajeev Kumar occasion... protests here and there, besides challenges in court. They had not seen this coming,” said a Trinamul state vice-president. “There was already a groundswell against the actions, attributed directly to Shah.”

Mamata left the CBI office after the likes of lawyer-MP Banerjee — who led the arguments for the defendants — assured her that bail for the leaders was just a matter of time.

“Kalyan’s over-confidence cost us, in the end. Instead of going about chest-thumping after the bail from the lower court, he should have consulted major legal minds, who are always willing to help, such as (the Congress’s senior lawyer-leaders) Abhishek Manu Singhvi and Kapil Sibal,” said a Trinamul source.

“The CBI had not allowed them (the leaders) to leave for hours, despite the bail. It should have struck us then that the agency and its boss (Shah) were preparing for something we hadn’t factored in,” he added.

Through the day, Mamata and her party not only found support from most prominent non-BJP players, including her otherwise bitter Bengal rivals, the CPM and the Congress, but also from civil society — even its apolitical sections — as criticism of the CBI and its “political masters” was widespread in social media.

The criticism was mainly on two counts: the likes of Suvendu Adhikari and Mukul Roy (both former Trinamul heavyweights, now in the BJP, co-accused in the Narada case) apparently being spared; the timing of the arrests.

With Mamata inside and hundreds of Trinamul workers outside, the historic Nizam Palace on AJC Bose Road had become a key flashpoint in the relentless skirmishes between the Bengal government and the Centre over the past few dasy.

As protests grew across the state, with an increasing build-up outside the Nizam Palace resulting in a short-lived flare-up, the Trinamul leadership was quick to douse the flames.

Orders went out to nodal persons, urging restraint.

The crowds outside the Nizam Palace remained through the day.

Since the evening, the Trinamul workers and supporters were preparing for celebrations to welcome the arrested leaders’ release on bail. At night, after the high court development, the dejected lot launched a sit-in demonstration against the CBI and the BJP.

A large police contingent was deployed on AJC Bose Road by the state administration to ensure there was no further flare-up as the CBI already used the excuse of the afternoon incident to demand transfer of the case to another state.

At night, while preparations were underway to move the quartet to the Presidency Correctional Home at Alipore, sources in Trinamul said steps were being taken to ensure that all the four got hospitalisation-like arrangements.

“All the four have numerous comorbidities and this is the peak of the second wave of Covid-19. They are all middle-aged or aged. We have to ensure they don’t fall ill from all this,” said a Trinamul MP. While Chatterjee, the youngest of the four, is 56, Mukherjee, the oldest, is 76.