It became a pattern. Again and again over those months, the court heard, Michael pointed the finger at his brother, always insisting he himself had nothing to do with the killing.

But the recordings kept catching him out.

The other undercover officer, Anna, got to know him separately, and during a covertly captured conversation in a café in December 2023 she put it to him that his nephew had killed somebody.

“My nephew didn’t kill nobody,” Michael replied. “It was my brother.”

By now the investigation had broken cover. Michael had been arrested and questioned about the murder, then released – while, unknown to him, the undercover operation quietly continued around him.

Then, in a police interview in March 2024, came the slip that helped place Michael at the scene.

Denying he had been covered in blood that night, Michael blurted out: “Well if I’m up the top of the alleyway keeping look[out]… how would I have got blood all over me? Come on.”

Nobody – not the police, not his family, not a single witness – had ever accused him of being the lookout, prosecutor John Price KC told the jury.

That detail existed nowhere but in Michael’s own memory of the night.

In trying to talk his way out, he had placed himself at the top of the alley as Anthony was beaten to the ground.

And it explained a mystery, buried in the files since 1984.

Two minutes after the attack, a young man had rung 999 from a phone box near the alley, asking for an ambulance for a man who was bleeding heavily – then hung up without giving his name.

Nothing was found, and the call was dismissed as a false alarm.

Only someone who had been there could have known so quickly, Price said.

That caller, the prosecution told the jury, was 15-year-old Michael Stewart – the lookout, the first to run, raising the alarm for the dying man his own group had left behind.