Brennan had been due to start work with the RFU as an England physio until his role in the systematic use of fake-blood capsules during matches was exposed.
After being banned from rugby for two years he had carried on working in private practice, but the Health Professions Council disbarred him from practising in September. That means his career is in ruins unless his legal challenge at the High Court in London, which was due to start on Tuesday, is successful.
Brennan helped fabricate the blood injury to winger Tom Williams during Harlequins' Heineken Cup quarter-final defeat to Leinster in April 2009.
The panel's ruling stated: "The dishonesty...continued over a number of years and ended not as a result of his own volition, but only because of the player's subsequent admission.
"The behaviour indulged in by Mr Brennan was dishonest, premeditated and continued over a considerable period of time.
"While the panel acknowledges that the incident on April 12, 2009, was instigated by Dean Richards, by that date Mr Brennan had been offered the job with the England team and could have resisted any pressure put on him."
Deciding to make an example of Brennan, the panel added: "It is the sanction...necessary for the public and other professionals to understand that behaviour of this sort is unacceptable."
Brennan had admitted to five instances of faking blood injuries, the first of which occurred during Harlequins' 2005-06 season.
On three occasions this was for player welfare, while Brennan said the fourth was to get an unnamed player in a key position on the pitch following a sin-binning of a team-mate. His High Court appeal will be heard by Mr Justice Ouseley.