A genetically modified crop boosted with a dietary supplement could be grown for the first time in Britain as early as this year following a request by scientists to conduct a controversial field trial at a heavily-protected research site in Hertfordshire.

The government-funded researchers have applied this week for formal permission to grow the first GM plants that are designed to produce high yields of the same omega-3 fatty acids found in fish oil, which are linked with a healthy diet.

They could receive the go-ahead within three months and the first GM seeds could be sown this spring on the same high-security plot of land within the large estate owned by Rothamsted Research in Harpenden, where GM wheat trials took place successfully over the previous two years without being destroyed by activists.

If the fish-oil field trials are successful, the technology could be used to produce food that is enriched with the omega-3 fatty acids linked with alleged health benefits such as a lower risk of cardiovascular disease – although the scientific support for these claims is mixed.

The GM crop fortified with the genes for making fish oil is among the first of a new generation of genetically engineering food plants designed to boost vital dietary supplements – so-called “nutraceuticals”. Anti-GM activists in the Philippines last year destroyed field trials of GM “golden rice”, which is fortified with genes for precursors to vitamin A.

Wary of public opposition to the trial, the Rothamsted researchers emphasised that they are more interested in showing it is possible to produce commercial quantities of omega-3 fatty acids to supply the fish-meal market for farmed fish which currently accounts for 80 per cent of the omega-3 fish oils harvested from wild-caught marine organisms.

Rothamsted Research applied on Monday for a licence to conduct the field trial from the Department for Environment, Food and Rural Affairs. The scientists could be given the go-ahead within 90 days, following a public consultation and an inquiry by the government’s scientific committee overseeing the release of GM organisms into the environment.

GM crops could help to solve the problem of over-fishing

The open-air field trial behind a high wire fence and 24hr CCTV will involve the planting of a flax-like plant called Camelina sativa engineered with synthetic omega-3 genes that trigger the production of the “fish oil” in the seeds of the harvested crop.

Although omega-3 is often described as fish oil, it is in fact made by microscopic marine algae that are eaten or absorbed by fish. Among the many health claims made about omega-3, the strongest relate to its supposed benefits in reducing the risk of heart disease – although some medical authorities have questioned the evidence.

“Despite claims that fish oil supplements can help prevent numerous conditions including cancer, dementia, arthritis and heart problems, there is little hard evidence for them,” says the advice on the NHS website.