Darren Smalley was the only person tried over the April 2015 alleged sexual assault in Halifax, in the eastern province of Nova Scotia. Charges against three fellow sailors in the case were dropped or stayed.

According to local media, the judge said the complainant's testimony was simply not credible.

"I'm relieved this has come to an end. It's been a hard four years," Smalley told reporters as he left the courtroom.

"With having allegations hanging over you for such a long time, it's taken it's toll on me both mentally and physically."

His lawyer added that he will now return to Britain and looks forward to getting on with his life.

The complainant had testified in court that the four men sexually assaulted her during a drinking party at the Shearwater military barracks at the home of Canada's Atlantic fleet.

She said she fell sleep next to a sailor on a bunk and awoke face down and naked while being raped by several men.

The four British servicemen were visiting Halifax to participate in an armed forces hockey tournament.