As political leaders arrive for the 61st annual Bilderberg conference in London, police have implemented a no-fly zone and used anti-terror laws to close-off streets to traffic.
The annual meeting of the secretive Bilderberg Group, which features some of the world's most powerful policymakers and politicians, is a lightening-rod for anti-capitalist protestors who see the private club as a conspiracy to "fix the global economy" for private interests.
The meeting being held at the Grove Hotel in the North London suburb of Watford is being attended by Henry Kissinger, the former U.S. secretary of state, Timothy Geithner, the former U.S. treasury secretary, former Italian Prime Minister Mario Monti and George Osborne, the U.K. finance minister.
(Read more: Bilderberg's Glamour and Secrecy Comes to the UK)
The heads of Barclays, McKinsey & Company, BP, Goldman Sachs and HSBC will also be in attendance as well as Google's Eric Schmidt and Amazon's Jeff Bezos.
A spokesperson for the Bilderberg Group told CNBC that members had been arriving all day and the event would formally begin on Thursday evening.
Police confirmed to CNBC that anti-terrorism traffic regulations and a no-fly zone had been put in place.
Around 200 protesters gathered outside the hotel on Thursday afternoon, a reporter on the site from the Watford Observer newspaper told CNBC.
A large 7-foot fence had been erected around the hotel building where the group is due to meet. According to the reporter, cars featuring blacked out-windows had been entering the grounds of the hotel, amid protesters shouting "pay your taxes" and "scum".
Its predicted the number of protesters will swell as the meeting progresses into the weekend.
"Hertfordshire Constabulary fully recognize the right of people to protest lawfully and peacefully and will always facilitate demonstrations of this nature in the county," Alison Roome-Gifford, the assistant chief constable at Hertfordshire police said in a press release.
"[However] any individuals trying to gain access to these grounds will be refused entry by the event security team who will have the support of a prompt proportionate policing response if required."
U.K. opposition politician Michael Meacher travelled to the event to speak at the protest on Thursday, despite his Labour Party colleague and shadow finance minister, Ed Balls, attending the Bilderberg conference.
"World elite of finance capitalism meets secretly to fix global economy in own interests," he said on Twitter.
U.S broadcaster Alex Jones - famous for his recent on-air fracas with CNN anchor Piers Morgan over the issue of gun control – also attended the protest and said on Twitter that he expected thousands of protesters to travel to Watford to be part of the fringe protests.
"We the people demand justice & we are taking the planet back!," he said.