Keir Starmer today called for England to outlaw the smacking of children.
Wales today made it illegal for parents to hit kids, meaning any type of corporal punishment - including smacking, slapping and shaking, has been made illegal.
Scotland had already brought brought in a ban in November 2020.
But parents in England and Northern Ireland still have a defence of “reasonable punishment” if, for example, they do not leave a red mark or use an implement like a cane or belt.
Critics of Wales’ law change have said it will criminalise parents, but the Welsh Government has insisted the move is about protecting children's rights.
And today Sir Keir - a former Director of Public Prosecutions - called for other areas to follow suit.
Speaking on a visit to Stevenage, Sir Keir said the move was "welcome".

"What it does is give children the protection that adults already have, and that is the right thing," he told reporters.
"I would like to see the rest of the UK step into line here, because I think, well, Welsh Labour have taken a lead here and they're absolutely right to protect children in the way that they now have."
In England and Northern Ireland smacking is unlawful, but such an assault is allowed as long as it constitutes "reasonable punishment".
Whether the defence is accepted depends on the circumstances of each case.
It takes into consideration factors such as the age of the child and the nature of the contact, including whether it left a red mark or was carried out with a fist or implement such as a cane or belt.
Wales’ "smacking ban", as it is known, was brought in under the Children (Abolition of Defence of Reasonable Punishment) (Wales) Act 2020.
It means children will get the same protection from assault as adults, and the law will apply to everyone, even those visiting Wales - as is the case with all Welsh laws.

Parents or anyone who is responsible for a child while the parents are absent can now face criminal or civil charges if they are found to have physically disciplined a young person in any way.
Labour First Minister Mark Drakeford said: "The United Nations Convention on the Rights of the Child makes it clear that children have the right to be protected from harm and from being hurt and this includes physical punishment.
"That right is now enshrined in Welsh law. No more grey areas. No more 'defence of reasonable punishment'. That is all in the past."
He added: "There is no place for physical punishment in a modern Wales."
Deputy minister for social services Julie Morgan called the day a "historic moment for children and their rights in Wales".
Viv Laing, from NSPCC Cymru/Wales, said: "Until now, children were the only group in our society who it was acceptable to strike in certain circumstances. We don't allow the physical punishment of adults or animals, so it is absurd that we have for so long with children. NSPCC Cymru/Wales has long been clear on this, and now, at last, the law is too."
Chair of the Royal College of General Practitioners Wales, Dr Rowena Christmas, said: "The evidence is absolutely compelling that physically punishing a child can be harmful to the wellbeing of both child and parent.
"It offers no benefit that cannot be gained from another method of discipline but is associated with a broad range of harms that can last a lifetime."
Stephen Thomas, headteacher of Ysgol y Bryn Llanelli, said: "Physical punishment has no place in raising children. Providing consistency, good routines and being role models for our children in the values we would like them to display creates good people."