Campaigners have hit out at Defra’s approval of a four-year GM potato trial, over concerns it could threaten food safety.

The trial was approved with little fanfare by farming minister George Eustice on 27 April, and will see the potatoes planted in an open field at The Sainsbury Laboratory in Norwich.

Campaign group GM Freeze this week bemoaned the controversial decision, calling it a “regulatory blank cheque”. The group has raised concerns that despite field trials usually following a programme of greenhouse experiments, most of the potatoes in the trial have not yet been created or tested in a controlled environment, which could present risks to food safety and GM contamination.

Prior to consent for the trial, a multi-agency objection was signed in March by 33 organisations, including farmers, scientists, retailers, caterers and environmentalists. It argued that the application for a field trial was premature, and would be of no benefit to society.

In Defra’s letter of consent, Eustice said the trial would have to stick to various restrictions, including the site not exceeding 1,000 square metres, with no more than 1,500 GMOs to be planted at the site during the period from May 2017 to November 2021.

“We are deeply concerned that Defra has signed a regulatory blank cheque in consenting to the planting of experimental potatoes which have not ever been analysed in a test tube, much less properly studied under controlled greenhouse conditions,” said Liz O’Neill, director of GM Freeze.

“Writing on 27 April, Eustice stated that he had ‘taken advice from the Advisory Committee on Releases to the Environment’. However, that ACRE advice explicitly states that it ‘does not include a food safety assessment’ and ‘has not addressed issues that are not safety concerns’.

“Good governance is about more than narrow technical risk assessments and it is entirely unacceptable to dismiss concerns about the wider economic, social and societal impacts of GM crops. These may not be in ACRE’s remit but that doesn’t mean they should be disregarded by our elected representatives.”

A Defra spokeswoman said: “The potatoes produced in this trial will not be entering the food chain and pose no risk to human health.”