A married man who stabbed a pregnant woman to death was today jailed for life and told he must serve a minimum of 21 years before parole.

Taxi driver Siraj Arif, 31, unleashed a "merciless and sustained attack" on Saiba Khatoon, 27, who was 19 weeks pregnant with his child, Manchester Crown Court heard.

The victim's son, aged seven, saw his dying mother covered in blood, lying in the kitchen of their home in Darlington Road, Rochdale, following the attack on May 7 this year.

The boy woke neighbours knocking on their doors shouting, "My Mum! My Mum!", Kim Hollis QC, prosecuting, told the court.

Father-of-three Arif, who admitted murder, later gave himself up to police claiming Ms Khatoon had attacked him and he "snapped".

The defendant, of Armstrong Hurst Close, Rochdale, was at the centre of a "complex" relationship with two women - his first wife Nazia, who spoke no English, and Ms Khatoon, a westernised Muslim who he "married" in a second Islamic wedding ceremony.

Ms Khatoon had also previously been married to a doctor, Anwar Ul-Haq, in 2004 but they divorced after she bumped into Arif at a wedding and the pair began an affair.

But the day of the murder the victim's sister, Sara Ali, had gone to Arif's family home to "confront" his wife over her allowing her husband a second "marriage" - and "spoke of her sister's pregnancy" which left the wife "very upset", the court heard.

Hours later Arif had finished his shift and went to Ms Khatoon's home.

She suffered 15 stab wounds, including two punctures to her heart and wounds which went straight through her body and injured her spine.

Some of the injuries were to her hands and back as she tried to crouch down and defend herself during the attack in her kitchen, the court heard.

In a call to police before giving himself up, the defendant told officers: "We had a fight. She picked a knife up and she told me she was going to kill my baby or I'll kill you...we ended up having a fight and I ended up grabbing the knife and shoving it in her...that's what I did."

Anthony Hayden QC, mitigating, told the court: "On the 7th of May, entirely out of character he snapped.

"He has at least had the courage to own up to this offence and plead guilty."

Arif gave no reaction as he was jailed for life but wiped away tears when Mr Hayden told the judge he could not simply leave his first wife for Ms Khatoon because he still loved her.

Passing sentence Judge Michael Henshell told him: "It was a merciless and sustained attack on a young woman in her own home who was 18 or 19 weeks pregnant, while her seven-year-old son was in the house."