The UK's spy chiefs and Interpol will join a new taskforce aimed at tackling modern forms of slavery.

The heads of MI5, MI6 and GCHQ will be among those invited to attend sessions of the group set up by Theresa May.

The Prime Minister used a meeting in the margins of the UN General Assembly summit in New York to push for international action to take on the criminal gangs behind the modern-day slave trade.

Ahead of the talks with leaders including Australia's Malcolm Turnbull and Nigerian president Muhammadu Buhari, Mrs May said she wanted the kind of international co-operation seen in the fight against drug trafficking and gun running.

In the UK, the Prime Minister has announced a taskforce of ministers and officials to address the issue, which she chairs.

The heads of the intelligence services and the Metropolitan Police will attend when required, along with representatives from international law enforcement agencies Europol and Interpol.

The Government has earmarked £33 million from the UK aid budget to tackle modern slavery in high-risk countries from which victims are regularly trafficked to the UK, with at least £5 million due to be spent in Nigeria.

Mrs May said: "The UK is leading the world with our efforts to stamp out modern slavery. Just over a year since the Modern Slavery Act came into force, convictions are up, more victims are getting support and there are more police investigations into this abhorrent crime.

"But there is still much more to do. Across the world an estimated 45 million people are enduring experiences that are simply horrifying in their inhumanity. That's why I am determined to drive forward international action to eradicate modern slavery.

"Just as the criminals cross borders, so we need a radical new approach that crosses borders - sharing intelligence and joining up investigations.

"This is standard in the case of drugs trafficking and the trade in illegal firearms and there is no excuse for our law enforcement authorities failing to do this when it comes to modern slavery.

"We owe it to the innocent men, women and children who are being tricked into a life of hard labour and abuse to rid our world of this evil.

"Just as it was Britain that took an historic stand to ban slavery two centuries ago, I am determined that the United Kingdom will once again lead the way in defeating modern slavery and preserving the freedoms and values that have defined our country for generations."

The Prime Minister urged her counterparts and experts to develop a model for tackling modern slavery based on strong law enforcement, improving transparency in business supply chains and measures to support victims.

The international co-operation Mrs May is calling for could see joint investigations and intelligence-sharing arrangements.