Detectives clung to the hope that the girls had gone on a "great adventure". But they confessed concern about the chances of finding the girls alive, with no confirmed sightings of Charlene Lunnon and Lisa Hoodless since they set off for Christchurch School, St Leonard's, near Hastings, East Sussex.
More than 400 officers, military police and Gurkhas from the Princess of Wales Own Regiment in Canterbury searched the town and surrounding rural areas yesterday.
Detective Superintendent Jeremy Paine, of East Sussex Police, said the search was extended to the outskirts of London after several unconfirmed sightings of the two best friends in Plumstead, West Drayton and Ruislip.
Next month is the anniversary of the death of Charlene's mother, Sandra. Her ashes are at a crematorium in Ruislip, west London. The child may have wanted to go and see a plaque dedicated to her memory.
There were also suggestions that Lisa may have been anxious about her home life, but Det Supt Paine refused to elaborate. He disclosed that police were questioning registered paedophiles in the area, as well as investigating claims that the two girls had boasted about running away.
Searches of their housesindicated that they did not take any extra clothes with them. They were thought to be wearing school uniforms when they vanished.
"It could be a great adventure and they may come back," said Det Supt Paine. "My instinct is that they are in the London area, but as time goes on it gets more and more worrying."
Charlene's father, Keith, a drug and alcohol adviser, said she had very little money, having already spent most of her weekly pocket money of pounds 2.50.
Neighbours of the two families said yesterday that they feared the worst. Peter Watson, who regularly saw the two girls on their way to school, said: "It may have started as an adventure but it has gone on too long now."
Nicola Woolcott, who has five children and who has lived in St Leonard's all her life, said: "An adventure would be over by now. They would have wanted their beds, their dinner and their mothers. We have all thought about running away but most of us come back when it gets dark."
As darkness fell last night the girls" parents were preparing to spend their third night without news of their children.
Det Supt Paine said: "We still don't know if we are dealing with runaways or something more sinister. I must believe they are capable of sustaining themselves away from home for so long because the alternative does not bear thinking about."Reuse content