The call by the NSPCC chief to change the law so that failing to report child abuse is a crime has been welcomed by a lawyer who represents 176 victims of disgraced TV presenter and serial abuser Jimmy Savile.
Liz Dux, a lawyer with Slater & Gordon, said: "The NSPCC's backing for mandatory reporting is a welcome and significant moment in our fight to protect future children from predators like Savile, Harris, Smith and Hall.
"This, coupled with an announcement earlier this week by Theresa May that an independent inquiry is to be held, signals we are moving in the right direction - the victims will take some heart.
"Universally the victims I work with say they want change, they support mandatory reporting.
"We must not pass up this opportunity to protect our children and we must not delude ourselves that outrages like these ones will never happen again - if we don't act they could."
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The suspect, 35-year-old Willie Corey Godbolt, has been arrested and was being treated for a gunshot wound in hospital.
Mohanna Abdhou, known as Montana, was out with friends when two attackers cycled up to them and opened fire in Brent, north-west London.
The US president tweeted that Mrs May gave him "full details" of the incident during talks while he attended summits in Europe.