A ?gang? war, simmering for some time behind the walls of Presidency jail, exploded on Tuesday evening, scalding the campus and sending the head warder and an undertrial to hospital.

Flashpoint was reached on Tuesday evening during the routine headcount around 5.30 pm. A section of the high-security prison campus turned into a battlefield as rival groups slugged it out for close to an hour.

The face-off pitted the group allegedly led by head warder Uttam Pramanik against the other headed by high-profile prisoner Rashid Alam, alias Gabbar.

The showdown was triggered by the alleged harassment of undertrial Ram Chandra, part of the Gabbar gang, by some jail staff.

During Tuesday?s headcount, Pramanik allegedly beat up Chandra for ?showing disrespect? to him. Gabbar, accompanied by Bikash Gomes, Palash Das and some other undertrials, then came to Chandra?s rescue and attacked Pramanik.

A free-for-all ensued as the two groups exchanged blows and even hurled bricks. When things spun out of control, jail superintendent Kamal Kumar Mukherjee and the jailers were alerted.

A police team was rushed to the spot to break up the rival groups and slam the bars on the undertrials.

Chandra and Pramanik, who had sustained injuries on their head and legs, had to be hospitalised.

When contacted, jail superintendent K.K. Mukherjee said: ?I rushed to the spot and the situation was brought under control? I do not know whether any nexus exists between jail staff and undertrials. Action would be taken if some staff are found guilty.?

According to a jail official, this was the second such flare-up in the past six months at Presidency jail. ?Undertrials have formed gangs inside the jail and they operate in connivance with jail staff. Some warders have also formed their own ?gangs?, resulting in frequent friction between rival groups,? he explained.

So, if Gabbar, a lifer, heads one gang, another lifer Jagga heads another. Likewise, warders have two groups ? one backed by Gabbar and another by Jagga.

?In September 2005, Jagga and his gang members had beaten up a warder ?from? Gabbar?s gang. Things had turned ugly and then inspector-general of prisons Joydeb Chakraborty had to visit the jail and take stock of the situation. What happened on Tuesday was a sort of revenge taken by Gabbar and his gang,? pointed out another jail official.

?Gabbar and his gang had been waiting for an opportunity to hit back ever since the day Jagga beat up a warder belonging to their camp. And Pramanik was the prime target, since he is the head warder,? the official added.