Many leaders have quit the Congress, but Ghulam Nabi Azad's five-page resignation letter on Friday delivered the maximum sting by describing former Congress president Rahul Gandhi as "immature" and "childish" and accused the leadership of "foisting a non-serious individual" at the helm of the party.

Rahul Gandhi's actions were criticised by leaders such as Himanta Biswa Sarma and Hardik Patel as well when they quit the party. In his letter addressed to Congress President Sonia Gandhi, Azad mentioned Rahul Gandhi seven times, accusing him of running the party through a "new coterie of inexperienced sycophants".

Azad, 73, who has been associated with the Congress for nearly five decades, also attacked party chief Sonia Gandhi for applying the "remote control model that demolished the institutional integrity of the UPA government" to the party.

He also reminded Gandhi that she was just a "nominal figurehead" and all the important decisions were being taken by Rahul or "rather worse his security guards and PAs".

Azad also slammed Rahul Gandhi's conduct within the party and singled out his action of tearing off a government ordinance in "full glare" of the media for the loss of the Congress party in the 2014 Lok Sabha elections.

"One of the most glaring examples of this immaturity was the tearing up of a government ordinance in the full glare of the media by Shri Rahul Gandhi," he said. "The said ordinance was incubated in the Congress Core Group and subsequently unanimously approved by the Union Cabinet presided over by the Prime Minister of India and duly approved even by the President of India.

"This 'childish' behaviour completely subverted the authority of the Prime Minister and Government of India," said Azad, who served as Health Minister in the UPA-II government. Assam Chief Minister Himanta Biswa Sarma drew similarities between Azad’s letter and the one he had written while quitting the Congress in 2015.

The problem in the Congress is that everybody knows Rahul Gandhi is "immature, whimsical and unpredictable" but his mother is still trying to promote him, Sarma said in Guwahati. Sarma, a close confidant of the then Assam Chief Minister Tarun Gogoi, quit the Congress in 2015 to join the BJP. He was largely credited with BJP’s rapid strides in the northeastern states and was made chief minister of Assam after the party was re-elected to power last year.

He had said that Rahul Gandhi appeared keen on feeding biscuits to his pet dog when he had met him to discuss issues related to Assam. Gujarat leader Hardik Patel, who was the working president of the state Congress, also claimed that the Congress senior leadership lacked seriousness about all issues.

"Whenever our country faced challenges and when the Congress needed leadership, Congress leaders were enjoying abroad," Patel said in his resignation letter in May in an apparent dig at Rahul Gandhi's frequent foreign trips.

Patel had said that big leaders of Congress in Gujarat were far away from issues of the state but were more focussed on ensuring that chicken sandwiches for leaders who have come from Delhi were delivered on time.

(With PTI Inputs)