New medical evidence detailing the impact of a second trial on Brittany Higgins’ mental health is expected to result in the charge being dropped and the trial not proceeding.

The ACT Director of Public Prosecutions Shane Drumgold will make an announcement after reviewing the material at 10am on Friday.

He is expected to exercise his prosecutorial discretion to drop the charge against Bruce Lehrmann, the man accused of sexually assaulting Ms Higgins.

The bombshell decision follows new psychiatric advice that a planned retrial of the rape allegations posed an unacceptable risk to Ms Higgins’ mental health.

As a result, former political staffer Mr Lehrmann, who has consistently maintained his innocence, will no longer be prosecuted over the allegations.