It has been revealed that the cost of security measures needed to protect genetically modified (GM) wheat during a controversial trial in Harpenden climbed to over £2 million.

Rothamsted Research has today (Thursday) officially released the full results of its GM wheat trial, which show the crop did not – despite expectations – repel aphids.

The trial, which involved wheat being genetically modified to resist the pest, was conducted from 2012-13, after being given the go ahead by the Department for Environment, Food and Rural Affairs (Defra).

But the research provoked anti-GM campaigners, with hundreds of people descending upon Rothamsted in 2012 to support a protest organised by campaign group Take the Flour Back.

Campaigners at the time said they wanted to “remove the threat of GM contamination”.

While the total cost of Rothamsted’s research - funded entirely by the Biotechnology and Biological Sciences Research Council (BBSRC) - was £732,000, a further £444,000 was spent on fencing to protect the site from intruders and prevent the entry of wild animals.

And, an additional £1,794,439 was provided by the BBSRC for security measures in response to threats of vandalism and attempted criminal damage by anti-GM activists.

An Old Etonian eco warrior was fined £4,300 for damaging GM crops at Harpenden in 2012, after he scattered organic seed and pulled up trial crops.

In a statement released this afternoon, Rothamsted admitted that its scientists had been left disappointed by the trial results, as they failed to echo what was hypothesised and initially seen in laboratory experiments.

Professor Huw Jones, senior molecular biologist with oversight for the genetic changes in the plants, said: “As scientists we are trained to treat our experimental data objectively and dispassionately, but I was definitely disappointed.

“We had hoped that this technique would offer a way to reduce the use of insecticides in pest control in arable farming.

“As so often happens, this experiment shows that the real world environment is much more complicated than the laboratory.”

Aphids are serious pests of wheat and other arable crops grown in the UK, transmitting viruses and reducing the amount produced.

Farmers spray insecticides to control aphids when infestations become severe, due to a lack of an alternative approach.

Scientists at Rothamsted, one of the oldest agricultural research centres in the world, conducted experiments to discover whether wheat could be genetically modified to produce an aphid alarm pheromone, and whether it would repel aphids in the lab and field.

This would allow farmers to reduce insecticide spraying, benefiting the environment and making farming more sustainable.

While the GM wheat did not repel aphids in the field, the five-year project did achieve some success.

In a world-first, the use of genetic engineering to provide wheat able to produce the aphid alarm pheromone was successful.

The full results have been published in Scientific Reports.