Relatives of a West Midlands woman murdered in an 'honour killing' on the orders of her elderly mother-in-law took their protest about the handling of the case to Downing Street yesterday.

Grey-haired Bachan Athwal, a 70 year-old grandmother known as "mummy dearest", may die in prison after being jailed for life for the murder of Surjit Athwal, from Coventry. She will not be eligible for release until she is 90 years old, an Old Bailey judge ruled yesterday.

Bachan lured Heathrow Customs officer Surjit to India on the pretext of going to two family weddings after learning she was cheating on her son Sukhdave.

Surjit, a 27-year-old mother to two young children, disappeared "off the surface of the earth" after the trip in December 1998 and her body was never found.

Bachan boasted to family members she had arranged for her daughter-in-law to be strangled and her corpse thrown into a river, and a "cunning, calculated plot" was hatched to cover up the crime.

Terrified that the controlling matriarch, a mother of six and grandmother of 16, may exact the same fate on them, none of the relatives came forward to police until years later to reveal their "dark family secret".

Sukhdave, 43, was also jailed for life, with a minimum term of 27 years. The sentence was only greater than his mother's due to her advanced age.

The pair, both of Willow Tree Lane, Hayes, west London, were convicted of murder by an Old Bailey jury in July.

After yesterday's sentencing, Surjit's relatives handed a letter in to 10 Downing Street, criticising the initial handling of the case. They said the case was never raised formally with the Indian government and had been left "abandoned and deserted" for years.

Meanwhile, suspects in the Punjab "continued to escape justice".