Detective Chief Inspector Nick Wallen, in charge of the case, said the attack which killed Louisa Denby was “brutal and frenzied.”

Speaking at a news conference afer Nathaniel Flynn was jailed for life for the murder and the attempted murder of Jason D'Arcy, 9, he said: “We can only imagine the impact of Flynn’s actions upon her family who continue from the consequences of her loss to this day. Louisa was a lovely lady.”

Life sentence for Nathaniel Flynn for murder of his grandmother 

Det Chief Insp Wallen commended the courage of Jason D’Arcy, who “suffered a terrifying attack at the hands of Flynn, and yet has shown great strength in recovering so well.”

He said it was “a truly isolated and deeply unusual incident, quite unlike any I have encountered in my career as a police officer.”

And he paid tribute to the people of Shipley, who assisted police to quickly detain and arrest Flynn. “Policing works at its best when supported by members of the local community, and that support was truly there.”

Det Chief Insp Wallen read a statement on behalf of Jason’s father, Lee D’Arcy, in which he said: “Jason is still recovering from what happened that day, but he is making very good progress and we are hopeful that the support he has been given by everyone will aid him in his recovery.”

A statement by Barbara Robinson, Louisa Denby’s daughter, on behalf of the family, said: “The sudden horrific murder of our mother has had a devastating effect on our family. Now we hope to rebuild our lives, although our mother will never be forgotten.”

Police have released a CCTV image of Flynn entering a convenience store near his grandmother’s home in Windhill to buy beers after murdering his grandmother, holding a walking stick police believe he used in an attack later in the day.