A man and woman found guilty of assaulting their developmentally challenged roommate have been sentenced.

Johnathon Rick was sentenced to eight years behind bars and Cynthia Anderson was given six years in a London court on Tuesday.

In his sentencing, Justice Andrew Goodman said, "One could get sickened that boiling water could be poured - causing serious, painful burns...[the injuries were] life-threatening, permanent and serious."

Each was found guilty of one count of aggravated assault back in September, in connection with scalding the woman at their south London apartment. She spent 13 days in hospital recovering.

The couple has already spent four years behind bars after being accused of confining and torturing their roommate and charged with 10 separate counts in 2011, but were released after being convicted on the single charge pending the sentencing hearing.

The sentencing may mark the end of the second trial in the case. A new trial was ordered after the female roommate involved recanted portions of her story.

After time served, Anderson was able to walk out of the courthouse freely on Tuesday.

Rick will spend an addition 18 months in jail, though his lawyer Frances Brennan says he is considering an appeal.

"Mr. Rick has maintained his innocence throughout this process and I expect we'll pursue his appeal rights at this point."

Brennan also asked the judge to place Rick in protective custody at a different facility after he was reportedly assaulted by inmates and guards at the Elgin Middlesex Detention Centre.