With speculation of a Congress and Left alliance in West Bengal ahead of the Assembly polls reaching a crescendo, the ruling Trinamool Congress has slammed the grand old party for entering into a "shameless" alliance with an ideological foe. Party leader Derek O'Brien compared the Congress with a watermelon. "The Congress party in Bengal is like a watermelon - they are green from outside and red inside," he said. While O'Brien was working hard to demonstrate that there was little difference between the Congress and the Left, Communist Party of India national secretary Amarjeet Kaur said categorically there was no Congress-Left tie-up in the offing in the state.