The Bridgewater Three may not have been freed after 18 years in prison, if a provision 'sneaked' into the 1996 Criminal Procedures and Investigation Act had existed when they were convicted.
Clause 5.8 of the Code of Practice, which was formulated by the Home Secretary Michael Howard in December last year, was introduced without a parliamentary debate.
It states that relevant material in a case following a conviction at a trial on indictment should be retained for a minimum of three years.
For summary trials the minimum period is one year.
Anthony Scrivener QC, former Bar Council Chairman, and head of 2-3 Gray's Inn Square, said in the wake of the Bridgewater conviction reversal: "Clause 5.8 was very cleverly sneaked into the code of practice, which was not voted upon.
"It provides that all material used in prosecution can be destroyed after three years. And remember, if you are trying to get a reference from the Home Office, there can be delays of up to six months to get a reply."
He said other well publicised miscarriages of justice, such as the Birmingham Six, Guildford Four, and Winston Silcott case would not have been exposed.
A spokeswoman for the Crown Prosecution Service was unable to comment.