Newsbeat political reporter
The patrols keep a watch for young people out late and at risk
New measures to get children off the streets at night are being rolled out across the country.
Operation Staysafe will give police the power to hand young people over to social workers.
It'll soon be in place in more than 30 different parts of England.
Newsbeat's spent a night out on a Staysafe patrol to see how they work.
One 14-year-old girl isn't getting arrested - but a confrontation with two uniformed police officers has left her sobbing.
At 10 o'clock on a Saturday night, she's been picked up as she walks through the local park in Preston's St Matthews area with a boyfriend.
She's one of dozens of young people approached in the area by police as part of Operation Staysafe.
PC Graham Metcalfe asks: "Do your mum and dad know where you are?"
She's still sobbing as she answers, "Yeah. I'm allowed out until half past 10, and then I've got to go in."
But PC Metcalfe isn't convinced by her story, so he decides to escort her home.
As he radios for a minibus, he explains: "It's 10 o'clock, it's pitch black, and she's 14 years of age, out in the park with a young lad. If her parents are happy with that, well, that's fine."
Back at her house, PC Metcalfe and his partner explain to her parents what's going on.
As they do so, the minibus drives off to bring back social worker Caroline Wallace.
By the time Caroline arrives it's 11 o'clock at night. She says: "You're not in trouble. But do you understand why the police have picked you up and returned you home?"
'At risk' children
Caroline says her role as a children's social worker is "ensuring parents are aware of their responsibilities. The concern tonight was that this young person was out, and couldn't provide any contact details for her parents".
Elsewhere, a 14-year-old boy was found with a bag of cannabis and a 13-year-old was discovered drinking lager.
In both cases their parents were called up and made to meet with social workers.
Perhaps most worrying was a nine-year-old boy who was found wandering alone near a main road.
He was two miles from his home wearing only thin clothes, even though there was a thick frost on the ground.
Social workers described him as at "serious risk".
Operation Staysafe currently runs in only a handful of places. But the government says it's about to be be picked up in more than 30 areas around England where youth crime is considered a problem.
Inspector John Ainsworth - who runs Preston's Staysafe - makes no apology for confronting families with social services.
He briefs his officers, "some people are worried that social workers are going to be prying into their families. That's absolutely correct. That's exactly what we are going to do".
A big part of Operation Staysafe is that the families involved get follow-up calls from the authorities in the days and weeks after a young person is picked up. It may be daunting for some people.
For the girl's mum though, she's just pleased to have her daughter home safe.
She described her feelings about the police and the night's events to Newsbeat.
"Shock. But I'm glad. They've done their job, you know. Anything could have happened. She ended up on the park. I knew she was out tonight, but I never knew she was on the park".