Hundreds of protesters have been blocked by police from accessing the GM wheat trial at Rothamsted Research in Hertfordshire.

Anti-GM campaign group, Take the Flour Back, had threatened to rip up the trial crop during a mass protest on Sunday 27 May.

Early estimates suggested about 200 protesters descended on the site at about noon.

But they were met by a heavy police presence of up to 500 police officers and a standoff took place at the gates of the research site.

The police were backed by a court order secured by Rothamsted Research.

The order was approved directly by the home secretary and banned the public from entering the land or using nearby footpaths until midnight on Sunday (27 May).

Protesters withdrew to a rally at Rothamsted Park where speakers slated the trial and raised concerns about the spread of GM genes into commercial crops grown on farmland close to the site.

Take the Flour Back spokeswoman, Kate Bell, put the number of protesters at more than 400 and branded the gathering as the “start of a new resistance”. She did, however, accept the group’s main aim of destroying the crop had been thwarted.

In a statement she said: “More than 400 growers, bakers and families from across England, Ireland, Scotland, Wales, France and Belgium marched against the return of  open air GM field testing today.

“Take the Flour Back linked arms with their European counterparts, notably France’s Volunteer Reapers1 and walked calmly towards the site, before being stopped by police lines.

“We wanted to do the responsible thing and remove the threat of GM contamination, sadly it wasn’t possible to do that effectively today. However, we stand arm-in-arm with farmers and growers from around the world, who are prepared to risk their freedom to stop the imposition of GM crops,” she concluded.