A septuagenarian widow of Indian origin and her son were sentenced to life in prison by a British court on Wednesday for plotting the murder of her daughter-in-law for allegedly having an extramarital affair.

Bachan Athwal, 70, was ordered to spend a minimum of 20 years in jail for the murder of her daughter-in-law Surjit Athwal, while her son Sukhdave, 43, will spend a minimum of 27 years behind bars.

"The pair of you decided that the so-called honour of your family members was worth more than the life of this young woman," Judge Giles Forrester said.

"You, Bachan, were the head of that family. I have no doubt you exercised a controlling influence over other family members."

According to Prosecutors, Bachan arranged for her daughter-in-law to "disappear off the surface of the earth" in December 1998, after discovering she was having an affair with a co-worker at London's [Images] Heathrow airport.

Her body was never found, but Bachan, a mother of six and grandmother of 16, boasted to her family that she had arranged for her brother to strangle her and throw the corpse into a river.