Jeremy Corbyn’s vow to stop the controversial TTIP trade deal is “opportunistic and misguided”, an organisation representing bosses has said.

The Institute of Directors, which lobbies on behalf of business interests, accused the Labour leader of “rushing to judgement” on the EU-US trade treaty before it was finalised..

Mr Corbyn this morning pledged to “reject TTIP and veto it in government” under its current terms.

Campaigners have long warned that the deal, which is being negotiated in secret, would allow corporations to sue governments that harmed their profits because of the inclusion of a clause called “Investor State Dispute Settlement”.

Previous trade treaties to include similar systems have seen national governments forced to pay to multinational corporations for scrapping tax breaks and introducing regulations.

Allie Renison, head of EU and trade policy at the Institute of Directors, said an “overwhelming majority” of IoD members supported TTIP.

“In an interconnected world, easy movement of goods and services across borders is vital to maximising Britain’s economic prosperity,” she said in reaction to Mr Corbyn’s speech.

“An overwhelming majority of IoD members support the US-EU trade deal because a reduction in trade barriers would give a boost to both exporters and importers alike.

Labour leader Jeremy Corbyn delivers a speech on the EU in central London (Sky News)

“We urge the Labour party to wait until the agreement has been finalised before rushing to judgement. In both Europe and America the principle of free trade is under attack from opportunistic or misguided politicians.

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

“Now more than ever we need our leaders to stand up and make the positive case for how trade benefits both businesses and consumers through lower prices, a greater variety of products and services, jobs associated with increased exports, and the innovation which competition spurs.”

The organisation says nine out of 10 of its members support TTIP.

Mr Corbyn this morning said his mailbag was full of people asking him to stand up to the deal, however. “Many people are concerned rightly, that it could open up public services to further privatisation – and make privatisation effectively irreversible,” he said in a speech in central London on Thursday.

“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."

Last month French president François Hollande also said he could not accept the TTIP deal in its current form.