Paige Chivers left the family home in August 2007 following a family row
A teenager who vanished from her home in Blackpool almost two years ago could be with a travelling fair, police said.
Paige Chivers, 17, has not been seen since leaving home in Bispham in August 2007 following a family argument.
Officers have said they are keeping an open mind about her whereabouts and were following new leads suggesting she could be with a travelling community.
Paige is one of five UK children whose photo is to feature on balloons for International Missing Children's Day.
Ahead of the event, two Lancashire Police officers have gone to London to raise awareness of Paige's case.
The officers have joined Kate and Gerry McCann and other families of missing children on London's Southbank to release the campaign balloons.
The International Missing Children's Day, which is organised by the Global Missing Children's Network (GMCN), will take place on 25 May.
Lancashire Police said the investigation into the Blackpool teenager's disappearance, on 23 August 2007, remained the "most heavily resourced" in the force.
In recent weeks officers have been looking into new leads which link Paige with the fairground community in the south of England.
Det Ch Insp Dermott Horrigan said: "Visiting fairgrounds was an important part of Paige's life.
"She is an independent, spirited young character and one new line of enquiry that we are currently investigating suggests she could be working or associating with the fairground community elsewhere in the country.
"We still need people to come forward with information, particularly anyone who has had contact with Paige, or whom Paige has been part of their lives since she left."
Detectives have made a number of arrests in connection with her disappearance, but no one has been charged.
Paige is described as white, 5ft 5in (1.65m) tall, with brown hair and a Playgirl tattoo on the back of her neck.