¿ Around £7m is the estimated cost of policing and security

¿ The visit has been planned for 18 months. It is 85 years since the last State visit of a US president; Woodrow Wilson in 1918

¿ Up to 100,000 demonstrators will line the streets of central London for the demonstration on Thursday

¿ A total of 14,000 Metropolitan Police officers - including several hundred armed officers - will be on duty in London over the four days, plus 1,300 in the North-east for the visit to Sedgefield

¿ Also present will be dozens of sniffer dogs and electronic detection devices for bombs and other weapons

¿ At least one Metropolitan Police helicopter will be watching from the sky at any one time. Several police launches will patrol the Thames

¿ There will be unknown numbers of SAS soldiers and MI5 and MI6 officials on standby should any incident occur

¿ An estimated 250 United States Secret Service agents will arrive to protect the president

¿ Two armoured presidential limousines, one presidential aircraft and one presidential helicopter will take the president around