Prior to the commemorative programme, the police had warned officers not to provide security for the event in a wireless message.
Speaking at the programme, Mr Pratt questioned what the use of the police is if they are not ready to provide security at such events with the former president and other leaders in attendance.
"The police must provide reason why former president John Dramani Mahama cannot be provided with security when he attends public events like this one," he said.
He expressed his "shock" and "disgust" about the police conduct, warning that the "people defeated British colonial rule at the time the British were said to be ruling the world."
He also warned the security services not to forget events in Haiti in the 1950s when under Papa Doc and Baby Doc tyranny, the people drove them out of power.
The by-election which was held on January 31, 2019, was marred by a shooting incident at the residence of Mr Kwasi Delali Brempong, the NDC candidate, which resulted in injuries to 18 persons.
The Justice Emile Short Commission was established on February 8 this year by President Akufo-Addo to make a full inquiry into the circumstances of and establish the facts leading to the events of the associated violence during the by-election held on January 31.
The move was in accordance with Article 280 Clause 3 of the 1992 Constitution.
The Commission submitted its report on March 14, to the President and it has made some key recommendations to be implemented.