The government should stop demonising children, a charity said after judges ruled in favour of a child who said a curfew breached his human rights.
The Children's Society said it had been concerned about the police powers ever since their introduction under the Anti-social Behaviour Act.
High Court judges ruled police could not force youngsters to go with them as the law did not include arrest powers.
The Metropolitan Police said it would fight the ruling with the Home Office.
In a statement, the Met also said it would continue to use the powers which allows officers to take a child under the age of 16 home within a designated dispersal zone.
The dispersal zones, designed to tackle anti-social behaviour, also allow police to move on groups they feel may cause trouble.
Boy W, who was described in the court as a model student had challenged dispersal zones in Richmond, south-west London.
The judge acknowledged that W, who was 14 at the time, had been 'distressed' when Community Support Officers approached him while he was in the zone and told him he had been acting suspiciously.
Kathy Evans of The Children's Society said the case of showed most young people were law-abiding citizens.
She said: "Young people up and down the country were concerned about this law and our England-wide NOP poll at the time found that a large majority of young people said curfews were unfair, but the government wouldn't listen.
"Home Office figures show that youth crime is decreasing.
"It is time to stop targeting and demonising young people as the cause of the problem and include them properly as citizens and members of their communities."
The Metropolitan Police said in a statement that child protection and vulnerability were a priority.
And where appropriate, police would continue to remove children to a place of safety, not always their home address under the Children's Act .
The leader of Richmond Council ,Tony Arbour, said he feared the decision would make young people "stick two fingers up at police who ask them to disperse".
Dominic Grieve says the powers are questionable
He said: "This was a useful tool in our armoury to keep Richmond the safest borough in London.
"As far as I can tell this has more or less neutered the power that we had."
Dominic Grieve, the shadow attorney general, said it was questionable whether police should have the power to arrest young people who had not committed a crime.
"That's what distinguishes (curfew orders) from the dispersal order, where there are considerable powers precisely because the behaviour of those congregating together is causing concern," he said.
"I want to talk to government ministers about it, but it does seem to me that the court's criticism of the curfew order may well be correct.
"The government themselves didn't see fit to attach the power of arrest to the curfew orders in the first place."