The elected mayor of Watford has written to the Prime Minister voicing concern about the potential impact the Bilderberg security operation will have on the county’s police budget.

Dorothy Thornhill penned a letter this week to David Cameron saying she found it “galling” that the Hertfordshire taxpayers could shoulder the cost of policing a meeting for some of “the wealthiest people in the world”.

The Liberal Democrat said she also wanted the Government to understand the stresses the secretive conference had placed on the town and its public services.

The Bilderberg Group is due to start its three-day conference at The Grove hotel on Thursday and police are gearing up for a sizable security operation backed by anti-terror laws and a no-fly zone.

Elected mayor Dorothy Thornhill.

Representatives from the Government including Chancellor George Osborne and cabinet minsiter Ken Clarke will be attending the conference at the five-star hotel, as well as shadow chancellor Ed Balls.

They will be spending three days with the heads of global corporations such as Google, Amazon, Goldman Sachs and BAE Systems as well as other leading figures such as Christine Lagarde, head of the IMF, and former US secretary of state, Henry Kissinger.

The event is expected to draw a large number of protesters unhappy about the lack of transparency from the group, which does not release any minutes of its discussions.

In her letter, which was sent yesterday, Mayor Thornhill said the town's local authorities and police had been given little time to prepare for the conference.

“The police have been forced to make quick arrangements with minimal consultation with residents, and these have had ramifications,” said the mayor.

She continued: “I am also very concerned about the additional strain this must put on Herts Police’s budget, which had already been set for the year ahead.

“While I realise the conference is funded by a cocktail of contributors, the local constabulary will surely have to pick up a substantial part of the tab, which is all the more galling when the participants in the conference are among the wealthiest people in the world.”

Yesterday senior officers from Hertfordshire Constabulary confirmed the Bilderberg Group had made a “donation” to the policing costs of the conference.

However they declined to reveal the amount and said the final cost of the operation was still uncertain.

Last week the Watford Observer revealed that Hertfordshire Constabulary was in discussions with the Home Office to secure an emergency grant to help meet the costs of policing the Bilderberg conference.

The Home Office will not confirm an application had been made from the constabulary. Yet the minimum a force can apply for is one per cent of its annual budget, which in Hertfordshire’s case would mean a sum of at least £1.7 million.

In her letter Mayor Thornhill said she was confident the police were prepared for the event and that it would pass off peacefully.

She also acknowledged that the conference would have a “positive impact” for the town as it meant extra trade for The Grove.

The Grove hotel.

The mayor concluded the letter, which was copied to Chancellor George Osborne, saying: “I am however confident the police are prepared for every eventuality, be it a major terrorist threat, or disruption from protesters or aggrieved residents.

"The police have been in contact with the main protesting group and we believe the conference will pass off peacefully.

“However please do convey to your representatives attending later this week that this has only been achieved through considerable hard work from people here, who are still trying to do their day job. It has been a difficult few weeks, and it is important those in Central Government understand that.”