A still from the Modern Slavery ad

A still from last year's modern slavery awareness TV advertising campaign

David Cameron has vowed to stamp out the 'abhorrent trade' of human trafficking as he unveiled a new rules for British businesses to tackle the problem.

Companies with a turnover of £36 million or more - a figure every business in the FPJ Big 50 Businesses surpassed - will be forced to prove what they are doing to stop slavery and trafficking in their supply chains.

The prime minister was speaking as he became the first serving British PM to visit Vietnam.

The new rules, which will apply to more than 12,000 firms, will begin in October.

Under the measures - which are part of the Modern Slavery Act - all large companies will be required to publish an annual statement setting out what steps they are taking to ensure that slave labour is not being used.

The government has also promised funding for an additional shelter for survivors of trafficking, particularly women or children, and to help to prevent people falling into the grips of people smugglers in the first place.

David Noble, group CEO of the Chartered Institute of Procurement & Supply (CIPS), said: “With 11 per cent of British business leaders saying it is likely that modern slavery already plays a role in their supply chains, this is clearly a pervasive issue that concerns us all.

“We therefore welcome the new measure that requires large companies to publish an annual statement setting out what steps they are taking to ensure that slave labour is not being used.

'However, if the Modern Slavery Act is to have a chance of truly eliminating slavery from British supply chains, then the government must not limit the application of the act to large firms only.

'Modern day slavery is not a problem confined to the supply chains of large multinational corporations. On the contrary, SMEs can have long and complicated supply chains. In fact, our research shows that four out of five British SMEs say they are struggling to gain end-to-end visibility of their own supply chains. They are, therefore, perhaps in most need of guidance.'