POLITICAL indifference, ignorance, and a leadership vacuum in Whitehall mean that Britain, which once led the way in abolishing slavery, is now a "shameful shadow" of its former self, as the trade makes a comeback, a new report says.

It Happens Here: Equipping the United Kingdom to fight modern slavery, by the Centre for Social Justice, castigates those involved, from government ministers to social workers, for a "shocking" failure to prevent the spread of modern slavery in the UK, leading to sexual exploitation and the forced labour of people trafficked from overseas and within the UK.

The report says that the current approach to eradicating modern slavery is fundamentally wrong. Instead of aiding victims, it says, the system simply prosecutes many of them for immigration offences.

The investigation examined more than 1000 cases of exploitation of foreign and UK adults and children in agriculture, on building sites, and factories, brothels, and homes. It concluded that official figures were just "a pale reflection of the true size of the problem".

The Centre's managing director, Christian Guy, said: "We have been shocked by many of our findings. A leadership vacuum at the heart of Westminster; a messy legislative framework; frontline professionals - however well-meaning and brilliant in some areas - forced to swim against a tide of indifference if they wanted to fight this crime; official bodies failing in their duty of care, with little idea about the scale of the problem.

"Our research has uncovered a shocking underworld in which children and adults. . . 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."

The chief executive of the anti-trafficking charity Unseen, Andrew Wallis, who worked on the report, said: "We simply cannot be satisfied with our current efforts to prevent this vile trade from happening. We have allowed human beings in the UK to be bought and sold as mere commodities for profit, gain, or gratification. How on earth have we arrived at a place where there is no ambition or leadership to stamp out this appalling crime?"

The report makes more than 80 recommendations, and demands new anti-slavery laws, requiring companies with annual turnovers of more than £100 million to disclose publicly what efforts they make to ensure that their business practices are free from slavery.

The report also seeks to challenge the idea that trafficking is an international crime that affects mainly women and children. Of the 2077 potential victims identified by the UK Human Trafficking Centre in 2011, 40 per cent were men.

The Immigration Minister, Mark Harper, told the BBC: "The overall system we've set up is good. . . This is a crime that tends to be hidden, and we want to be sure people are more aware of it, and that people are more effective in dealing with the victims of it, and more effective in locking up the people engaged in this abhorrent crime."