A teenager has been arrested over the murder of a mother-of-two stabbed to death in a "frenzied" attack as she walked to work.

A witness saw how a man stabbed Carmelita Tulloch, 51, repeatedly as she lay screaming in Wickham Street, Vauxhall, at 9.05am yesterday morning.

Earlier today police arrested a 17-year-old boy in connection with Mrs Tulloch's death.

The grandmother had left her home in Scotson House on the nearby Ethelred Estate only five minutes before the attacker struck.

Her heartbroken husband, Prince Tulloch, 42, told The Sun of their last moments together.

"I saw her into the lift. I took her her handbag which she had forgotten, she hugged me, we kissed each other.

"She said, 'Take care, speak later. I'll phone you when I get to work'. I rang her mobile 15 minutes later. It just rang and rang."

He added: "She was such a loving person. I'm torn apart, I will never get over this. The man who did this should be executed."

Mr Tulloch was Carmelita's second husband. She had two grown daughters from a previous marriage, one of whom has a three-year-old child.

Police believe the murder may have been an unprovoked attack by a stranger or a bungled robbery, even though her bloodied handbag was found next to her with its contents apparently untouched.

"A struggle took place and she fell onto her back in the road," said Detective Superintendent Julian Worker, the investigating officer.

"A man was seen on top of her, stabbing her in a frenzied manner. For this reason, I believe the suspect would be heavily covered in blood."

The man ran off towards Jonathan Street.

Ms Tulloch, a black woman with highlights in her hair, was on her way to Vauxhall Cross to work. An air ambulance rushed to her air, but she had bled to death from a knife wound to the neck.

"This was a horrific attack on a 51-year-old lady, well known in the local area, who was simply walking to work," Mr Worker said near the crime scene.

"I am keeping an open mind re the motive. Her handbag was found at the scene but we are yet to recover a murder weapon."

Detectives are investigating whether Ms Tulloch had been followed.

She was dressed in a black skirt to just above the knee, a black top and distinctive grey strappy sandals.

Anyone who saw the victim or killer at the time of the attack can call 020 7321 9251.

Updated 7.33pm