Mr Corbyn has pledged to scrap the EU’s trade deal with the US. He joins a range of European politicians and campaigners in fighting against the partnership, which attempts to harmonise regulation between the two regions but also appears to weaken consumer protections and privilege companies.

The Labour leader has promised to stop the adoption of the deal if he is elected prime minister before it is completed. And he will also attempt to lead a rebellion in parliament, alongside dissident Tories and the Scottish nationalists.

What is TTIP?

Supporters of the deal argue that it is a necessary way of bringing US and EU regulations into line to allow companies to trade more easily. But while talks on the deal have remained secret, campaigners have argued that the deal will pose a huge threat to the NHS, privacy, the environment and other issues.

"Many thousands of people have written to me, with their concerns about the Transatlantic Trade and Investment Partnership (or TTIP) the deal being negotiated, largely in secret, between the US and the EU," he said during a speech as part of the Remain campaign. "Many people are concerned rightly, that it could open up public services to further privatisation – and make privatisation effectively irreversible. Others are concerned about any potential watering down of consumer rights, food safety standards, rights at work or environmental protections and the facility for corporations to sue national governments if regulations impinged on their profits."

The 6 reasons why we should be scared of TTIP Show all 6 1 /6 The 6 reasons why we should be scared of TTIP The 6 reasons why we should be scared of TTIP The NHS Public services, especially the NHS, are in the firing line. One of the main aims of TTIP is to open up Europe’s public health, education and water services to US companies. This could essentially mean the privatisation of the NHS. The European Commission has claimed that public services will be kept out of TTIP. However, according to the Huffington Post, the UK Trade Minister Lord Livingston has admitted that talks about the NHS were still on the table Getty The 6 reasons why we should be scared of TTIP Food and environmental safety TTIP’s ‘regulatory convergence’ agenda will seek to bring EU standards on food safety and the environment closer to those of the US. But US regulations are much less strict, with 70 per cent of all processed foods sold in US supermarkets now containing genetically modified ingredients. By contrast, the EU allows virtually no GM foods. The US also has far laxer restrictions on the use of pesticides. It also uses growth hormones in its beef which are restricted in Europe due to links to cancer. US farmers have tried to have these restrictions lifted repeatedly in the past through the World Trade Organisation and it is likely that they will use TTIP to do so again Getty The 6 reasons why we should be scared of TTIP Banking regulations TTIP cuts both ways. The UK, under the influence of the all-powerful City of London, is thought to be seeking a loosening of US banking regulations. America’s financial rules are tougher than ours. They were put into place after the financial crisis to directly curb the powers of bankers and avoid a similar crisis happening again. TTIP, it is feared, will remove those restrictions, effectively handing all those powers back to the bankers Getty/Bloomberg The 6 reasons why we should be scared of TTIP Privacy Remember ACTA (the Anti-Counterfeiting Trade Agreement)? It was thrown out by a massive majority in the European Parliament in 2012 after a huge public backlash against what was rightly seen as an attack on individual privacy where internet service providers would be required to monitor people’s online activity. Well, it’s feared that TTIP could be bringing back ACTA’s central elements, proving that if the democratic approach doesn’t work, there’s always the back door. An easing of data privacy laws and a restriction of public access to pharmaceutical companies’ clinical trials are also thought to be on the cards AFP/Getty Images The 6 reasons why we should be scared of TTIP Jobs The EU has admitted that TTIP will probably cause unemployment as jobs switch to the US, where labour standards and trade union rights are lower. It has even advised EU members to draw on European support funds to compensate for the expected unemployment. Examples from other similar bi-lateral trade agreements around the world support the case for job losses. The North American Free Trade Agreement (NAFTA) between the US, Canada and Mexico caused the loss of one million US jobs over 12 years, instead of the hundreds of thousands of extra that were promised Dave Thompson/Getty Images The 6 reasons why we should be scared of TTIP Democracy TTIP’s biggest threat to society is its inherent assault on democracy. One of the main aims of TTIP is the introduction of Investor-State Dispute Settlements (ISDS), which allow companies to sue governments if those governments’ policies cause a loss of profits. In effect it means unelected transnational corporations can dictate the policies of democratically elected governments AFP/Getty

Mr Corbyn made reference to that increasing division by arguing that the French's discontent means the British shouldn't support it either.

"A few weeks ago the French President, Francois Hollande, said he would veto the deal as it stands and to become law any deal would have to be ratified by each member state," he said. "So today we give this pledge, as it stands, we too would reject TTIP – and veto it in Government."

"And there is a challenge to the Prime Minister, if it’s not good enough for France; it’s not good enough for Britain either."

He asked that David Cameron "make clear" that if Britain votes for remain he would "block any TTIP trade treaty that threatens our public services, our consumer and employment rights and that hands over power to giant corporations to override democratically elected governments".

It has since become a central part of the debate around the EU referendum. Remain supporters have argued that the trade deal is a central reason for staying in the EU, while the Leave side has argued that it shows the danger of such huge partnerships.