The Home Office is planning to give inmates email access so they can keep in contact with their families.
A pilot project is on the drawing board to let some prisoners send plain-text emails to pre-approved email addresses.
A Home Office spokeswoman said the project will not go ahead until ministers have fully reviewed the proposal and are happy the emails will be monitored properly to prevent potential abuses.
The pilot scheme will see all emails sent to and from prisoners scanned to detect inappropriate content.
The spokeswoman said emails will also be archived with security staff actively monitoring content. If misuse is found the system will be locked down for up to six months.
The combined scanning and archiving of emails should spot any dubious use of email accounts, for example outsider email accounts being used by other people, the spokeswoman added.
The spokeswoman would not confirm press reports that Wandsworth Prison in south London will kick off the pilot scheme.