Diana Warner, 62, a retired GP, said: “One of the important reasons for coming out today was to say we’re all together. It’s not just nine.”

Chief Superintendent Nick Caveney, of Hertfordshire Police, said: “Not only is purposely blocking a highway incredibly dangerous, it also affects countless members of the public who are inconvenienced as a result.

“We understand how frustrating incidents of this nature are to the public, and want to reassure you that we have robust plans in place in order to minimise any disruption and to allow us to make arrests as quickly as we possibly can.”

A Greater Manchester Police spokesman said: “The majority of protesters had glued themselves to the road before being later removed by officers and detained on suspicion of causing danger to road-users (section 22a of Road Traffic Act).

“Disruption was kept to a minimum as officers ensured routes to the nearby motorway and airport weren’t blocked, and all roads in the area have now returned to normal. We thank the public for their co-operation despite their understandable frustration.”

West Midlands Police refused to comment when approached by the Telegraph. Home Office were also approached for comment.