The pair, who were aged 13 and 14 at the time of the attack, were convicted on Tuesday of using a range of weapons, including a coffee table and a computer printer to commit the killing in December 2014.

The girls, who cannot be named for legal reasons, were led out of the courtroom in tears after hearing the verdict, following a seven-week trial.

The jury heard that the victim, 39-year-old Angela Wrightson, was found with more than 100 injuries in her blood-spattered living room in the industrial town of Hartlepool.

Other weapons used in the attack included a television set, a shovel, ornaments and a kettle. The court heard that Wrightson was restrained and then tortured.

During the assault, one of the girls talked to a friend over Facebook, who overheard her say: "Go on. Smash her head in. Bray (hit) her."

The girls, now both aged 15, called the police at around 2:00 am in order to get a lift home.

While in the van, they posted a photograph on social media site Snapchat with the message: "Me.... in the back, on the bizzie (police) van again."

Prosecutor Gerry Wareham said the girls had shown little remorse.

"In our society it is hard to imagine that two girls of such a young age could be capable of such violence," her said.

"Given the severity of their assault on Miss Wrightson, one would expect the girls to have shown a degree of remorse in the wake of her death. Instead, they laughed and smiled while posing for a 'selfie'."