The 14-year-old, not seen since she disappeared after school on November 8, was found in Croydon on Tuesday and taken to Croydon Police Station.
She had lost weight, her hair had been cut off but – most importantly – she was safe.
Mother Lisa Pratt told the Advertiser she first knew her daughter was alive after a brief telephone conversation last Thursday.
She said: "When she went missing it was the end of the world really, and now she's back. It's been so strange; when they told me she had been found I was just shaking.
"It all started last week when we got a call from a random number just after 1am on Thursday morning. It was Shelley, and she was only on the phone for five seconds but she said 'I love you mum, I'm OK' and then the phone went dead.
"I think it was a cry for help because she knows how to make a number private but she didn't. We Googled the number and saw it had come from a pay phone in Soho."
Shelley Pratt's family had to move out while murder police dug up garden Then on Tuesday, at 2pm, Shelley was spotted in Croydon and taken to the police station. She is said to have lost a lot of weight and cut her hair off, but is still her usual "feisty self", according to father Tony.
He said: "She obviously wanted to be found because she hasn't been walking around Croydon before, she knew she'd get found here.
"I'm just so happy, I just want to give her a hug.
"I do want to know what happened and where she's been, but I'll give her time to open up.
"All I want to do right now is get her home and give her a hug and a kiss and tell her I love her, but I can't do that until they check where she's been, if she's hurt, or if any other girls are in danger."
As the Advertiser went to press yesterday (Thursday) Shelley was still in the care of social services, being checked over for any lingering physical or mental scars from her disappearance.
Mrs Pratt said she hoped Shelley would be back at the family home, in Crowther Road, South Norwood, soon.
The Pratts would not celebrate Christmas with Shelley gone.
They have kept their Christmas lights up outside the house, but refused to switch them on until their daughter is back and ready to open her presents, which have been kept wrapped up.
The days since her disappearance have been spent driving around and looking for her, encouraging neighbours and shops to display missing posters, appealing for more information.
Now, the lights are on and the family cannot wait to have Shelley back home.
Mrs Pratt said: "I couldn't believe it when I found out. Our police liaison officer called me, she asked me if I was sitting down.
"Then she just said 'We've got her, we've got her'. I was shaking, I couldn't believe it. Tony and I just rang everyone.
"We turned the Christmas lights on, we took all the missing posters down. We called her school, we told my son's nursery, all the other kids' mums were so happy for me.
"When we told our mums they were just crying."
Mr Pratt said: "We had so many visitors when we turned the lights on because they knew what it meant; the neighbours knew it meant she was back.
"I know when she's home, she might just go up to her room, she might not want to tell us anything at first, she might be different. But I'm going to give her that time."
The family now intend to celebrate their daughter's return with a party once she has settled back in to family life.
Mr Pratt said: "We're going to have a big celebration, a party, but make sure she's OK first.
"My brother just had a baby so she gets to meet her new cousin and it's the first anniversary of my dad passing away this week, so we're so happy she's home for that.
"The police have told us she is still her feisty self, which is brilliant. We don't want her to have changed.
"When they told us she'd had her hair cut we were shocked.
"Her hair was her pride and joy; she wouldn't even get it trimmed. We know someone must have made her do it.
"If she looks that different I could have passed her 100 times in the street while out looking for her and not realised.
"I'm just so happy she's home."
Shelley's sisters screamed with joy when they discovered she'd she had been found. Her five brothers and sisters – Anthony, 23, Tammy, 20, Tiffany, 18, JJ, 5, and Lewis, 3, are now looking forward to being reunited with their younger sibling. Tammy said: "I was in a shop when my mum rang me and said 'Shell has been found'. I just screamed, I couldn't believe it, I screamed so loud the shopkeeper asked me to be quiet. "I went and told the chemist because they had put up missing posters and they were shocked, and so happy for us. I can't wait to see her, to have her home. "As soon as she gets home me and baby JJ are going to take her upstairs to open her Christmas presents." Tiffany told the Advertiser: "I was on the bus when I found out. I made so much noise everyone looked at me. I rang my boyfriend screaming. "I just can't believe it, we're over the moon. I was crying, I still can't really believe it's real."