Federal prosecutors are expected to abandon their criminal prosecution of the military's former second-in-command, Vice-Admiral Mark Norman, CBC News has confirmed.

The Public Prosecution Service of Canada plans to withdraw the single breach of trust charge that was laid last year against the former vice chief of the defence staff, but has yet to confirm the reasons why, sources said late Tuesday.

Norman, who was also the former commander of the navy, was accused of leaking cabinet secrets in relation to a $668-million shipbuilding deal to lease a supply vessel.

The National Post first reported that the Crown would throw in the towel.

It came after the Public Prosecution Service of Canada took the unusual step, Tuesday evening, of sending out a notice to the media advising them that they "may wish to attend" court on Wednesday at 10 a.m.

The high-profile, politically charged case has seen the Liberal government face allegations of political interference from both the Opposition Conservatives and Norman's defence team, including Toronto lawyer Marie Henein.

The defence has claimed, in both arguments and court filings, that the Prime Minister's Office and the Privy Council Office have attempted to orchestrate the prosecution of the case. They also have alleged that former Treasury Board president Scott Brison tried to kill the lease deal on behalf of a rival shipyard.

The Liberal government, the public prosecution service and Brison have all denied the accusations, which were made in court and in court filings.

The tipping point may have come last week, however, when it was revealed that former parliamentary secretary — and soon-to-be former Liberal MP — Andrew Leslie had offered to testify for the defence.

Leslie, a former lieutenant-general, has intimate knowledge of the military procurement system and could have provided insight into the behind-the-scenes manoeuvring within the Liberal government as the case against Norman unfolded.

Fight for documents

The case has been a routine feature of question period in the House of Commons with the Conservatives hammering the Liberals over the slow pace of handing over federal government documents to the defence and for the refusal of officials to cover Norman's legal costs.

His lawyers have been fighting for access to federal documents for months. Hundreds of those documents have been released, but many key records were redacted.

The federal government has claimed the documents were blacked out to protect solicitor-client privilege and because they contain cabinet secrets. The defence team challenged those claims, arguing that Norman's prosecution is politically motivated.

The battle over documents focuses on up to 36 memos, analysis reports and emails involving the Privy Council Office and the Prime Minister's Office.

Uncertain future for Norman

The allegations against Norman first surfaced in January 2017, when his suburban home was raided by the RCMP and he was suspended from his job as vice chief of the defence staff.

It took the RCMP and the Crown more than a year to formally charge him with a single count of breach of trust, alleging he leaked cabinet secrets to both an executive at the Davie Shipyard, in Levis, Que., which leased a supply ship to the navy, and to a CBC journalist.

The Crown alleged there were 12 instances where details of what federal ministers were saying and thinking about the project were illegally revealed. The vast majority of those alleged incidents involved the negotiation period under the former Conservative government.

The prosecution also claimed that Norman leaked the results of a November 2015 cabinet subcommittee meeting under the Liberals, when, newly elected at the time, they decided to put the supply ship lease deal on hold for further study.

The government eventually reversed its decision and allowed the deal to proceed after a public backlash because of the leak.

It is unclear what Norman's future may be after Wednesday's court proceeding.

A veteran of three decades and eligible to retire, he was moved out of the vice chief of defence staff post, but has remained in uniform in a temporary duty post throughout the legal proceedings