The 76 year old was joined by actress Annette Crosbie at 10 Downing Street as he handed over the letter, which was signed by stars including Joanna Lumley and Eddie Izzard and backed by the National Anti-Vivisection Society (Navs) group.
The U.K. government is currently consulting on a review of a secrecy clause over animal experiments, and Blessed hopes the petition will convince officials the public should have greater access to details of the research procedures.
He says, "We are the guardians of this planet, and the animals are there for us to protect not to persecute. We must end the terrible suffering that animals endure in the laboratory."
Lumley adds, "The public has a right to know what animals are subjected to in the name of research, and the alternatives that could be used to replace them. The secrecy that currently shrouds such tests must end now."