Stating that he has his roots in Bengal, he said that the President was above party politics and was an upholder of the Constitution.
Party MP Derek O Brien, who received a copy of the letter dated July 2, told PTI tonight that Mukherjee appealed for support for his candidature.
In his letter, Derek said, Mukherjee spoke of his long political career and experience.
Party sources said the letter should have been sent to party supremo Mamata Banerjee, who would take the final decision.
Banerjee has already said that she would make known her decision three days before the Presidential polls on July 19.
