Detectives hunting for a missing 12-year-old girl are continuing to sift through hours of CCTV footage for a clue to her location.

Tia Sharp, who has not gone missing before, was last seen leaving her grandmother's home in New Addington, south east London, at around midday on Friday after telling relatives she was going to the Whitgift Centre in Croydon town centre.

Detective Chief Inspector Nick Scola said: "We are currently examining CCTV; at this time we have found no trace of Tia on the footage examined thus far, but this is an ongoing process which will take time.

"We have spoken to Tia's family and some of her friends and Tia has never gone missing before and it is extremely out of character for her not to return home or contact her friends or family.

"There has been a lot of activity on Twitter from Tia's friends and, whilst we would want to ensure that images of Tia and details of her disappearance are spread far and wide, we would urge people using social media to include the Incident Room number rather than their personal numbers.

"We have received a number of purported sightings but none are confirmed as Tia at this time."

Tia did not have her young person's travel card with her but some bus and tram drivers let children travel without one. Mr Scola said: "I am appealing for any bus or tram drivers in the Croydon area who recognise Tia's description to contact us. Of course if Tia herself is able to contact her family or the police, we urge her to do so."

Tia is white, 4ft 5in and slim, and was wearing FCUK glasses. She was dressed in a yellow bandeau top over a white bra with visible cross straps, light grey leopard print leggings and black and pink Nike high top trainers.

Speaking on LBC radio, Tia's grandmother, Christine Sharp, asked her to "come home".

She added: "She's very much loved, very, very much missed. Just contact any of us whatever way she can."