Efforts to tackle modern slavery in the UK, including the sexual exploitation of children, are in a state of crisis, a new report has claimed.
The Centre for Social Justice (CSJ) has attacked the Government for its "inadequate response" to the issue after an investigation by the independent think-tank uncovered a "shocking underworld" of human trafficking.
Its study found more than 1,000 adults and children were trafficked into or within the UK in 2011/2012, but the figure could be "only the tip of the iceberg".
Among the cases were British and foreign victims who had been forced into the sex trade, a life of crime or domestic labour.
British girls trafficked within Britain for the sex trade made up nearly one half of all UK slavery victims in the latest set of figures.
Christian Guy, managing director of the CSJ, said: "Our research has uncovered a shocking underworld in which children and adults, many of them UK citizens, have been forced into lives of utter degradation.
"Yet the authorities are either failing to understand the nature of this abuse or turning a blind eye to its existence. Our once great nation of abolitionists is a shameful shadow of its former self."
The think-tank is campaigning for a radical overhaul of measures to combat 21st century slavery, including bringing all human trafficking and modern slavery offences together.
It added that victims should be encouraged to come forward without the threat of facing prosecution over immigration breaches or crimes they have committed since being trafficked.
More training is also needed to ensure police officers, immigration officials and social workers recognise the scale and nature of the problem.
Guy added: "We have been alarmed to learn that British children being trafficked within the country are often viewed as somehow being complicit in their exploitation. This is absurd and unacceptable.
"Elements of control in these cases can be subtle and difficult to identify; this control frequently takes the form of sexual and other forms of violence, physical or emotional abuse, threats of violence towards family members or threats of public shaming."
A spokeswoman for the Home Office said the Government has already made significant progress in fighting trafficking.
She said: "Human trafficking is abhorrent and the UK Government is committed to combating this crime in all its forms.
"Investment in training for front line professionals to identify and refer victims, improvements in data collection, work with the private sector to protect workers and more personalised care and support for victims are already making a real difference.
"But the Government is not complacent and we will continue to work to improve and strengthen our approach to keep pace with emerging threats."
Immigration minister Mark Harper criticised the CSJ report. He told BBC Radio 4's World this Weekend programme: "It's slightly disappointing because I don't think it accurately sets out the position that I think is in government on this issue.
"We take the issue of human trafficking very seriously."