92-year-old Lal, who was popularly known as Mahashayji, breathed his last this morning. He had been admitted to the Lucknow hospital three days ago, CPI-ML sources said.
The leader, who belonged to Pilibhit district of the state, had taken part in 'Quit India Movement' in 1942 and had spent three years in jail.
After independence, Lal got associated with the communist movement and later joined CPI-ML.
The last rites of the veteran leader would be performed tomorrow morning in his native district, sources added.