THEY were complete strangers living hundreds of miles apart, but with a common interest in pure evil.

Vanessa George, Colin Blanchard and Angela Allen chanced upon each other over the Internet and developed a sickening online "love triangle" driven by their twisted desire to sexually abuse children.

In a case that could only happen through the existence of the web, both women e-mailed horrific, sexually violent scenarios to Blanchard as they competed for his affection before they turned their depraved fantasies into shocking reality, in what police called a "sick game of one-upmanship".

George – a married mother-of-two – photographed herself abusing babies at Little Ted's Day Care Unit where she worked in Plymouth and where around 150 images of children were taken. Allen boasted of her desire to watch men abuse girls.

Police have been unable to identify George's victims leaving around 30 sets of parents in the heartbreaking limbo of not knowing whether their son or daughter was abused. George, too, has added to their anguish by refusing to tell detectives just who her victims are.

The paedophiles met in person for the first time yesterday in the dock at Bristol Crown Court.

George, 39, who lives in Plymouth, hung her head as she pleaded guilty to seven sexual assaults and six counts of distributing and making indecent pictures of children. She denied one sex assault, which was ordered by the judge to lie on file.

Blanchard, 38, from Smallbridge, near Rochdale, Greater Manchester, admitted 17 child pornography counts and two sexual assaults on children. He also admitted a further charge of possessing extreme pornography.

Allen, also 39, from Nottingham, wept as she pleaded guilty to four child sex assaults and one count of distributing an indecent image.

Mr Justice John Royce warned them they faced substantial prison sentences as he adjourned the case for reports. He also urged George to co-operate with police in identifying all her victims.

He told her: "A lot of people are affected by this case and I would like your help."

Mr Justice Royce said many parents still do not know if their child was among the victims – but George "must know".

Addressing Nicolas Gerasimidis, George's counsel, Mr Justice Royce said: "Your client must know, it seems to me, who she has abused and who she has not.

"If I were a parent, I would want to know whether my child was abused or not. Would it not be decent for her to indicate who she has abused? It is a factor that I have got to take into account."

Defence lawyers for Allen and George suggested there was a degree of encouragement of the women by Blanchard. But the judge rejected suggestions Blanchard, whose wife knew nothing of his deviancy, was the main instigator who groomed the two women to abuse children.

Judge Royce said of George: "She is not a child. This is a married woman who can make up her own mind whether she indulges in this sort of activity or not."

The judge adjourned the case, provisionally scheduling sentencing for November 13.

George took up employment at Little Ted's in September 2006 after passing all appropriate criminal record background (CRB) checks.

Further inspections of the private nursery by regulator Ofsted confirmed this, and also awarded Little Ted's a good rating for "protecting children from harm or neglect".

Police believe the abuse began in September last year and carried on until June. The trio subjected their victims to humiliating abuse involving plastic golf clubs, sex toys and toothbrushes.

They recorded the abuse on their mobiles and then swapped the pictures via e-mail using unprotected accounts. The trio exchanged thousands of texts and dozens of e-mails, goading each other to more horrific acts.

Police found around 7,000 messages sent from George's mobile phone to Blanchard – some texts expressing love for him. But police say they have not been able to recover the "smoking gun" of a first message when the subject of child abuse was broached.

George later fantasised about abducting a child, after seeing a small boy in public toilets with his mother. The three wrote of meeting but never did.

Their depraved Internet relationship – and the abuse which fuelled it – was ended when child sex abuse images were found by a colleague on Blanchard's computer.

Blanchard had been on the sex offenders' register until 2007 after receiving a police caution for possessing indecent images.

Last night, Children's Secretary Ed Balls said it was "hard to comprehend" how George was able to "do such terrible things to innocent children".

"My department is in regular contact with Plymouth [City] Council who have been offering ongoing support to the staff and families," he said. "I expect the serious case review by Plymouth's Local Safeguarding Children Board to be completed as soon as possible."

He said it was important to "do everything we can" to prevent similar abuse in the future.

Detective Inspector Tony Creely, of Greater Manchester Police's sexual crime unit, said: "Blanchard, George and Allen sent thousands of messages between each of them.

"Blanchard expressed love for each woman, and they would reciprocate. They would discuss sexual matters of a crude and gross nature and the abuse of children in the texts and e-mails."

In one of their exchanges, Allen sent an e-mail to Blanchard on April 21 this year, showing her abusing a child. On the same day, Blanchard forwarded the e-mail to George.

The next day – April 22 – George sent Blanchard an e-mail containing 10 images of children abused by her. This e-mail was then forwarded by Blanchard to Allen.

Mr Creely said: "All of them were getting gratification from the texts and seeing who could have the worst idea. They were all as bad as each other."

Detective Inspector Costa Nassaris, of Devon and Cornwall police, said: "There's no suggestion of a financial reward. If you look at sex offenders generally, in only a small number of cases will the motivation be financial, and that is not the motivation in this case."

Speaking after the three had admitted their guilt, Detective Superintendent Michele Slevin revealed George had been "cooperative" – but still refused to name her victims. She said: "We have interviewed George five times and during these interviews she has been co-operative. Her motivation for not telling us the names of her victims at this time we do not know.

"We have asked her to let on the details which only she knows at this time. Hopefully after the comments of the judge today we will have further opportunity to speak with her and her counsel. Discovering their identities is our top priority.

"However, despite using a number of specialists and experts from around the country we have drawn a blank. Only she can reveal the names."

Ann Reddrop, head of the Crown Prosecution Service South West Complex Casework Unit, added: "These three individuals each acted in a way which ordinary people will find hard to understand. They may never have met but between them they committed shocking acts of child abuse.

"They showed complete disregard for the lives of their victims, their own families and those they worked with, all of whom have been left devastated by these crimes. George grossly abused her position of trust and while her victims may be too young to understand her crime their families do have to deal with those effects.

"Identifying her victims remains our priority but despite our best efforts we may never succeed. But we hope the families involved take some small comfort from today's pleas."

Det Con Andy Pilling of Greater Manchester Police's sexual crimes unit said: "Colin Blanchard's sick fantasies were the catalyst for a chain of events that led to the abuse of innocent children on a truly shocking scale." He said it appeared that Allen and George tried to please him in a "sick game of one-upmanship". He added: "Make no mistake, George and Allen are not victims of Blanchard's grooming."

Detective Superintendent Adrian Pearson, of Nottinghamshire Police, said they are still "baffled" as to how a "chance Internet encounter" led to the sick abuse. He said: "The thing that puzzles all the professionals in the hi-tech crime world is how on earth did three people meet on Facebook?

"It is accessed by millions of people, yet they somehow got on to such depraved, awful topics of conversation that led to sexual abuse of children, betrayal of trust and deprivation.

"The sheer unlikeliness of these three people being connected in that way will be a puzzle that will go on."