There will be a national investigation into the murder of six-year-old Arthur Labinjo-Hughes.

It comes as deputy prime minister Dominic Raab told Sky News: “The most vulnerable in our society need to have the maximum protection.”

The boy, from Solihull, West Midlands, was poisoned, starved and beaten by step-mother Emma Tustin, 32, and his father Thomas Hughes, 29, in a prolonged campaign of “evil abuse”.

A review will look into how social services and local authorities liaise with the criminal justice system to learn the lessons from Arthur‘s death.

The wider investigation will run alongside a review of the jail sentences of Arthur’s step-mother and his father.

And it will go beyond an independent local safeguarding review that is already under way.

Speaking to Sky News about the case, Mr Raab, who is also justice secretary and is a father of two young boys, said he “can’t begin to imagine how anyone could be that cruel”.

“We’ve had those sentences for the two parents, the Attorney General has made clear she wants to have them reviewed where we have a mechanism for doing so,” he told the Trevor Phillips On Sunday show.

“There will be a local safeguarding review which will look at the local authority’s actions – whether any lessons could have been picked up earlier, whether any warning flags could have been put up earlier.

“And the prime minister has made clear, as well as that, we want to see how social services and the local authorities liaise with the criminal justice agencies and what lessons further we can learn.”

The Department for Education is expected to make a formal announcement of the national investigation later on Sunday.

Education Secretary Nadhim Zahawi is due to make a House of Commons statement on the case on Monday.