'Inadequate' information released by authorities after Southport ...

What the police said, and when they said it, is important. On the evening of the attack, the Chief Constable of Merseyside Police, Serena Kennedy, held a press conference. She said "a 17-year-old male from Banks in Lancashire, who is originally from Cardiff" had been arrested in connection with the stabbings.

This was true - but police did not divulge family background details, including that the attacker's parents were Christians who had come to the UK from Rwanda.

The attacker was not named because he was one week shy of his 18th birthday. In that initial statement, the police said the motive was "unclear" but at that moment in time the incident was "not being treated as terror-related".

But Jonathan Hall KC told BBC Panorama that the authorities could, and should, have released more information after the attack.

"The public could have been told immediately that there had been an attack by a 17-year-old male who was black, British, born in Wales and has lived in the UK all his life," he told us.

"That he comes from a Rwandan background, and as far as the police were aware, from a Christian background. That it was not possible to say whether he had an ideology or that he was a terrorist. But the police are looking at, at pace, all the material that they found."