Online child protection chief Jim Gamble resigns
The chief executive of the Child Exploitation and Online Protection Centre (Ceop) has resigned in a row over its future, the BBC has learned.
The Home Office confirmed Theresa May had accepted Jim Gamble's resignation.
Mr Gamble said he did not believe the decision to assimilate Ceop into the National Crime Agency was in the best interests of children and young people.
Sara Payne, whose daughter Sarah was murdered by a paedophile, said it was "the worst possible news".
Ceop was set up in 2006 to help find and convict paedophiles.
The merger proposal was outlined by Ms May in July.
In a statement Ceop said: "The Child Exploitation and Online Protection Centre does not feel that it is in the best interests of children and young people for Ceop to be assimilated into the National Crime Agency, as was announced a short while ago.
"This direction of travel does not seem to have changed and Ceop's CEO, Jim Gamble, has therefore today offered his resignation to the home secretary with a four month notice period."
Mrs May said: "As chief executive Jim Gamble has done a great job at Ceop and made a huge contribution to protecting children. I wish him all the best for the future and arrangements for his successor will be outlined in due course.
"The government recognises the importance of child protection and wants to build upon the work of Ceop, but does not necessarily feel this is best done by creating a new quango."
It is understood that Ceop has made representations to the government since the announcement that its work was to become part of the proposed National Crime Agency.
Ceop is currently affiliated to the Serious Organised Crime Agency (Soca).
It is believed that Mr Gamble was keen on gaining more independence for the agency rather than allowing it to become part of a greater National Crime Agency.
It felt it would lose its identity and priorities given to its work would be devalued.
Ms Payne, whose eight-year-old daughter Sarah was murdered by Roy Whiting 10 years ago, said she was "disgusted" with the government for "betraying" Mr Gamble.
In a statement, Ms Payne, Shy Keenan and Fiona Crook - who jointly set up the campaign group The Phoenix Foundation - said: "This is the worst possible news and a devastating blow for UK child protection. Jim Gamble changed the face of child protection for the better, forever."
"We cannot begin to describe how disgusted we are with our own government for betraying him and for betraying all of our children. This cannot be allowed to happen; we must stand up and fight, we must do what is right for the protection of our children against the crimes of paedophiles."
Shy Keenan, who was abused as a child, also told the BBC: "We need an independent Child Protection Force, that is focused only on child protection, not soaked into a massive team where he has to fight every single day for funding to do what actually has to be done, and needs to be done," she said.
Claude Knights, director of anti-bullying charity Kidscape said Ceop had proven its worth and the news was concerning.
"It is so sudden as well and to have a person with as much experience as Jim Gamble being taken away from the horizon, really at such speed is a worry, because he is a leader in this field," she said.
Shadow home secretary Alan Johnson said Mr Gamble was a passionate advocate for effective measures to protect children from threatening people on the internet.
"Under his leadership the Child Exploitation and Online Protection Centre (Ceop) was gaining an international reputation for its tremendous work. Labour would have given Ceop the operational freedom it needed to become even more effective," he said.
"The government's plans will harm child safety networks. Their lack of consultation has led to the resignation of Mr Gamble who is highly respected within and outside of the organisation he served so well. His expertise will be badly missed."
Mr Gamble was head of Northern Ireland's anti-terrorist unit before joining Ceop and was one of five senior police figures shortlisted to replace Sir Hugh Orde after he stepped down as chief constable of the Police Service of Northern Ireland.
As Ceop chief executive Mr Gamble led calls for Facebook to set up a "panic button" to give reassurance for young users. The application has been downloaded tens of thousands of times since its launch in July.
Meanwhile, BBC home affairs correspondent Danny Shaw said that three other members of the senior management team of Ceop are to retire from the organisation.
A spokeswoman for Ceop said that these three departures do not follow Mr Gamble's resignation, as they had announced their intentions to retire beforehand.
However, she also said while each individual had their own reasons for leaving, their departures were not unconnected to the uncertainty and unhappiness within Ceop since the government announced it was to become part of the planned National Crime Agency.