Reform UK’s new justice adviser has called for the UK to introduce US-style “supermax” prisons.

Vanessa Frake, a former prison governor, said it would be “relatively easy” to convert some of the nation’s existing high-security facilities.

She made the comments as she announced she had formally joined Reform to play a leading role in the party’s law and order task force.

Nigel Farage said he wanted there to be debate on moving to a “supermax” prisons system after he was asked about the potential cost of making such a change.

He told a press conference in Westminster: “The supermax prisons, have we costed it? Have we thought it through? It is a debate.