The Queen and Prince Philip were at Sandringham at the time of the incident.
A Buckingham Palace spokeswoman said they would not comment as it was a police matter.
A man has been Tasered by police outside Buckingham Palace, Scotland Yard said today.
A Metropolitan Police spokesman said the incident took place at 11.55am but they did not have any further information.
A man was charged today with killing another man in a nightclub.
Ashley Milne, 22, of Peckham, south east London is accused of the murder of Jamie Sanderson, 20, at the Oceana nightclub in Clarence Street, Kingston, south west London, Scotland Yard said.
He will appear in custody at South Western Magistrates' Court on Monday.
A 47-year-old man has been arrested on suspicion of murdering missing oil executive Carole Waugh, Scotland Yard said tonight. The 50 year old, originally from Durham, went missing earlier this year.
Three men have been arrested for allegedly posing as police officers and planning to steal cash and credit cards from tourists in London.
Scotland Yard said the arrests came after some visitors to the capital were approached by men claiming to be officers who then took their credit cards or cash.
Three men, aged 32, 35, and 27, were arrested in central London for impersonating a police officer and conspiracy to steal.
They were in custody in a central London police station pending further inquiries.
Detective Superintendent Steve Osborn said: "Millions of visitors to London will sadly always be an attraction to criminals and it is important that people stay alert.
"We have officers out there on the street identifying and arresting those who are involved in crime."
A man has been arrested by police investigating alleged computer hacking.
Scotland Yard said he was held at his home in north London this morning by police working in conjunction with the phone-hacking investigation.
A spokesman said: "Officers from Operation Tuleta, the investigation into criminal breaches of privacy which is being carried out in conjunction with the Metropolitan Police Service phone-hacking inquiries, arrested one man at his home in north London at approximately 6.30 this morning."
He is the seventh person to be arrested as part of Operation Tuleta.
Scotland Yard has handed the Crown Prosecution Service files on five journalists for charging decisions in relation to Operation Weeting, the CPS said.
The senior policewoman leading Scotland's Yard investigation into illegal newsgathering is to retire after the Olympics, the Met has confirmed.
Deputy Assistant Commissioner Sue Akers is in charge of the three linked inquiries into phone hacking, illicit payments and computer hacking.
She has also been leading MPS inquiries into the potential involvement of intelligence services in relation to detainees held abroad.
Ms Akers has served for 26 years and in 2007 was awarded the Queens Police Medal for services to policing.
Enkarta Balapovi, 53, a butcher of St John's Wood, north London, faces one charge of trafficking within the UK and five counts of rape. Shanaz Begum, 56, a shop worker, also of St John's Wood, is accused of two counts of trafficking - the first into the UK and the second within Britain.
Shashi Kala Obhrai, 53, an optician, of Northwood, north west London, is charged with trafficking within the UK, ABH and making threats to kill. Balram Kumar Obhrai, 58, a computer entrepreneur from the same area, is accused of trafficking into the UK and making threats to kill.
Aleemuddin Mohammed, 34, a supermarket manager from Harrow, also in north west London, faces a similar count of trafficking into the UK and another of sexual assault on a female.Shamina Yousuf, 32, a secretary, of nearby Edgware, is charged with trafficking into the country and ABH.
Six people, including a butcher and an optician, have been charged in connection with trafficking an Indian woman, Scotland Yard has said. The suspects, all from London, face a number of counts including rape, sexual assault and making threats to kill the victim, from Hyderabad.
They will appear at Westminster Magistrates' Court on bail on June 7.