The boy ran to a nearby supermarket where he changed in a toilet, then took a taxi to another location in Edinburgh.

He called his aunt and uncle, who picked him up and alerted the police.

Mr McElroy said: “The accused admitted to them, like, ‘I did the murder so I’m going to do the time.’

“He told his relatives that people pulled knives on him so he had to defend himself.

“He explained to his uncle that the weapon he had was a large ‘Rambo’ knife.

Iain McSporran, defending, said the boy had been “exploited” from the age of 13 or 14 to be part of the “street level” drug trade.

He said an associate of Mr Carr’s wanted “serious violence” for the alleged theft of an electric scooter.

The boy believed he had been “set up” to be attacked that night.

But Mr McSporran said there was no evidence to suggest Ms Davidson was involved or aware of any planned attack.

He said: “He cannot rationally explain why he chose to attack Danielle Davidson.”

The boy is currently being held in a secure facility. He will be sentenced next month.