Undercover police confronted a “blogger” after he was spotted walking in the grounds of The Grove hotel ahead of the Bilderberg Group’s meeting next month.

The man, who identifies himself only as Sam, uploaded the footage showing a man dressed in a red golf top questioning him about his presence at the hotel, repeatedly asking him for identification and instructing him to turn his camera off.

The man is heard to say he is called Andy and works for Hertfordshire Constabulary.

After explaining that the hotel management had made a complaint to police about his presence on the site, Andy says: “They are concerned that you are up here and you could be anyone couldn’t you?

“Walking round [an area] full of nice cars, you could be here for any purpose whatsoever.”

Shortly after their discussion begins, the sound of a low-flying helicopter is heard overhead for a prolonged period and Sam comments that it is a police helicopter although this could not be confirmed.

Sam says: “I am at the moment being hovered over by a police helicopter and they’re following me going down the back entrance.

“This is a few weeks before it happens so you can only imagine what it is going to be like.”

Further down what appears to be Grove Mill Lane, Sam is again questioned by male and female uniformed officers in a marked police car.

Once again he is asked for his name and identification.

At this point a resident joins the argument, saying: “It’s a public footpath”.

The female officer tells Sam: “Because you have your camera it heightens our suspicions “You’re potentially someone who is planning on causing harm.”

The Association of Chief Police Officers (ACPO) has issued guidance clarifying the police have no power to prevent the taking of photographs, film or digital images in a public place.

It also states: “We must acknowledge that citizen journalism is a feature of modern life and police officers are now photographed and filmed more than ever.

“Unnecessarily restricting photography, whether for a casual tourist or professional, is unacceptable and it undermines public confidence in the police service.”

A Hertfordshire Constabulary spokesman confirmed public footpaths crossing The Grove estate were not currently closed to the public but could not say whether they would be during the conference from June 6 to 9.

Speaking about the film, a force spokesman said: “Hertfordshire Constabulary has a duty to prevent crime, maintain the Queen’s Peace, protect the public and prevent damage to property. “The public would expect us to respond to reported incidents in an appropriate and respectful manner as was the case in this interaction.”

Sam could not be reached for comment this week.