Despite government claims that public services will be protected from the EU's free trade agreement with the US, 42% of British people don't trust them to protect the NHS from privatisation.

A new survey, conducted by YouGov on behalf of 38 Degrees, found that a further 39% think the controversial Transatlantic Trade and Investment Partnership (TTIP) "would be bad for the UK", with just 13% saying it would have a positive effect.

When asked specifically about the NHS, 24% said their trust in the government to shield the NHS from privatisation has fallen over the course of a year, with just 4% saying it has risen.

Supporters of TTIP claim it will create jobs and wealth on both sides of the Atlantic. However, protestors have said it will simply place more power in the hands of the corporate sector.

Many fear that the NHS and other public services will be sold off to US investors and that if the NHS is not open to investors, they may be able to sue the government, using the investor-state dispute settlement (ISDS) clause which could be included in the free trade agreement.

At the moment, ISDS is off the agenda, after the EU Trade Commissioner Karel De Gucht temporarily removed it in January, pending the results of a public consultation, which are currently being analysed. However, he has since told this publication that he wishes the clause to return to the discussions, despite senior figures in global trade questioning its necessity.

The government told IBTimes UK earlier in August that the NHS is not an area that is up for discussion during TTIP negotiations.

A Department of Health spokesperson said: "We have no intention of allowing the TTIP to dictate the opening up of NHS services to further competition; and it will not do so. The NHS will always be free at the point of use for everyone who needs it."

However this stopped someway short of satisfying protestors' demands. Campaigners have called for David Cameron to confirm that the government's veto will be used to remove public services from the agenda.

Responding to the latest survey, Unite Secretary General Len McCluskey said: "This new poll from 38 degrees piles even more pressure on David Cameron to act and exempt the NHS from TTIP. David Cameron's silence is deafening. He is refusing to answer a very simple question. Are we going to exempt health from the EU US trade agreement?

"The people of this country didn't vote for selling-off our NHS and they didn't vote to make the sell-off irreversible by giving US companies the right to sue us in secret courts if the government tries to reverse privatisation."

Yesterday (August 28), in an open letter to European Union Trade Commissioner Karel De Gucht, a group of organisations warned that "fair, sustainable and safe food could permanently be damaged by the transatlantic trade deal on the table".

The letter, penned by the Institute for Agriculture and Trade Policy, Friends of the Earth and Compassion in World Farming, drew on a recently leaked TTIP document to conclude that the agreement could lead to US GMO standards being permitted in the EU, meaning "EU consumers could be faced with hidden GMO contamination of their food".

It goes on to warn: "We cannot have confidence that the draft measures designed to expedite agricultural and food trade between Europe and America will uphold to the highest standards the food safety safeguards that protect consumers and animals."

The latest developments come on the eve of a wave of protests across the UK, as part of a day of action against TTIP organised by 38 Degrees.