More than 1.2 million people signed a petition demanding that the honour, which was awarded in 2019 for services to the Post office and to charity, should be rescinded following a TV dramatisation of the miscarriage of justice last week.
"I continue to support and focus on co-operating with the Inquiry and expect to be giving evidence in the coming months. I have so far maintained my silence as I considered it inappropriate to comment publicly while the Inquiry remains ongoing and before I have provided my oral evidence," Vennells said in a statement.
"I am, however, aware of the calls from Sub-Postmasters and others to return my CBE (Commander of the British Empire). I have listened and I confirm that I return my CBE with immediate effect."
(Reporting by Paul Sandle; editing by William James)
