The National Crime Agency (NCA) reported on Tuesday that the number of potential trafficking in the UK has increased substantially between 2012 and 2013.

The NCA's monitoring system flagged 56 UK-born children who are possibly victims of sex trafficking industry. That represents a 155 per cent increase from 2012.

A smaller increase was seen among foreign-born children in the UK, where the NCA's monitoring system detected an 11 per cent rise in potential sex trafficking victims, bringing the number up to 88.

Looking at human trafficking of all kinds, including adults and children, sex, labour, and other types of trafficking, the UK saw a rise of 47 per cent in potential victims in 2013 compared with 2012.

The figues showed that 1,746 people from 112 different countries fell into the category of potential victims in 2013, with 1,122 of those being female and 450 children.

The most trafficked children by nationality were the Vietnamese, followed by the British, and then the Albanians.

Anita Tiessen, deputy executive director of Unicef UK was quoted by MSN News as saying she was "alarmed" by the figures.

"Trafficked children - regardless of whether they're born in the UK or born elsewhere and trafficked into the UK - face violence, exploitation and abuse of the most unimaginable kind," she said.

"The upcoming Modern Slavery Bill offers the UK a chance to develop world- leading anti-trafficking legislation, and Theresa May must seize this opportunity to protect trafficking's most vulnerable victims – children."

Lynda Rose, UK Director of Voice For Justice, was quoted on Christian Concern's website as saying: "Human trafficking is an appalling and degrading crime that creates misery for the victims, destroying their lives. But traffickers are difficult to catch, and the true scale of the problem remains unknown. I suspect.

"The figures released, though shocking, don't even scratch the surface.

"Whether it's sexual exploitation, domestic or agricultural servitude, or straight crime, somewhere near you today there's a victim of trafficking. The new anti-slavery bill is to be welcomed as an attempt to deal with the traffickers and protect victims."

Liam Vernon, head of the NCA's UK human trafficking centre, said the increase may not be down to actual trafficking, but rather better detection.

Speaking on the BBC News website, he said: "Increased awareness ... is a likely contributor to the increased number of referrals in 2013.

"We know that this is a crime which affects some of society's most vulnerable people, and some victims will remain undetected.

"The NCA is committed to relentlessly disrupting what is a criminal trade in human misery."

Home Office minister Karen Bradley said on the BBC that the figures were "unlikely to show the full scale of modern slavery nor the human suffering behind each statistic".

"The National Crime Agency is leading an enhanced and co-ordinated response to targeting trafficking gangs, we are increasing protection for victims, and we are strengthening legislation through a modern slavery bill," she continued.

"The bill will send the strongest possible message to criminals that if you are involved in this disgusting trade in human beings, you will be arrested, you will be prosecuted and you will be locked up."