Hertfordshire taxpayers will foot the bill for a major police security operation to protect a shadowy summit of world leaders taking place in Watford next month.

The Bilderberg Group of around 140 influential figures including royalty, politicians and business leaders will meet at The Grove from June 6 to June 9.

To ensure privacy, all 227 rooms at The Grove hotel are booked for the duration of the meeting.

Hertfordshire Constabulary has confirmed to the Watford Observer it will be policing the event, which is likely to attract protestors from across the globe.

Watford’s elected mayor, Dorothy Thornhill, said she had mixed feelings about whether the summit was a good thing for the town.

She said: “I have my concerns about it because it does attract people who can and do cause violence and disturbance.

“But I am confident the police will be able to minimise that and give them their right to protest.

“I am ambivalent about whether this is a good thing. It’s potentially a positive thing as long as things don’t kick off.

“I am concerned about the use of police resource but it is very good The Grove has been deemed a prestigious enough venue.”

The guest list for the “small, flexible, informal and off-the-record international forum” event is kept a closely guarded secret until the meeting is underway but attendees to previous events include Chancellor George Osborne, Labour peer Lord Mandelson, Nobel Peace Prize winner Henry Kissinger and Queen Beatrix of the Netherlands – who abdicated last month in favour of her son.

In 1993 Tony Blair denied to parliament that he had attended the Bilderberg meeting.

It is understood police are mounting a major security operation using a local rugby club as an operational base for the duration of the meeting.

A Hertfordshire Constabulary spokesman confirmed the event was taking place but declined to comment on operational policing details or the potential financial cost.

The spokesman added the force would “facilitate people who want to undertake peaceful protest” and that police leave would be cancelled if it was deemed necessary to maintain the peace.

The group’s annual meetings have in the past attracted storms of protests from campaigners who accuse it of hijacking the democratic process Among the more outlandish critics are writer and public speaker David Icke, who claims the group’s influential steering committee is made up of 12 foot lizards known as “Reptoids”.

Hertfordshire police and crime commissioner David Lloyd refused to comment on the police operation.