India, June 10 -- Trinamool Congress leader Sushmita Dev on Wednesday resigned as Rajya Sabha MP, second such jolt for the Mamata Banerjee-led party this week after the resignation of veteran TMC leader Sukhendu Sekhar Ray from the membership of the Upper House.

Ray resigned as Rajya Sabha MP alleging "unbridled corruption" and "anarchical rule" of the party.

TMC supremo Mamata Banerjee is facing the biggest challenge ever of keeping her party intact after losing the state to Bharatiya Janata Party (BJP) in the recently concluded assembly elections.

In back-to-back internal jolts, Mamata Banerjee's position as the commander of the party-in-chief of the party that was in power for three straight terms is under a threat with MLAs and MPs...