Donald Trump's state visit to the UK has begun, amid claims up to 250,000 protesters will attempt to disrupt proceedings. Mr Trump and his wife Melania were met at Stansted Airport in Essex by Foreign Secretary Jeremy Hunt on Monday morning.
Security arrangements will mirror those for his last visit in 2018, but be on a larger scale given this is a state visit, not just a working trip.
Mr Trump is accompanied by up to 1,000 staff, a motorcade and multiple helicopters for the trip, following weeks of careful planning by US and UK security teams.
The 20ft inflatable nappy-wearing Donald Trump baby blimp, first seen on the President's visit to UK last year, will fly over Parliament Square for two hours from 9am tomorrow, and a 16ft talking robot of Mr Trump sitting on a gold toilet is also planned.
Security experts warn that given Buckingham Palace's location between two public parks in the heart of a working city, significant measures will have been put in place.
"It's not just the normal threat of some violence and the assassination risk; it's also a threat and risk really around protests and the level of that protest," Richard Walton, the former head of counter-terrorism at Scotland Yard, told CBS News.
The president’s visit will see 10,000 police officers deployed in the capital. The security operation is expected to cost upwards of £25 million.
Uniformed police were already in position this morning and huge metal security barriers had been placed in front of Buckingham Palace. The Mall and other adjacent roads have been closed for the past two days as security infrastructure has been constructed.
An eight-foot ring of steel has also been erected around the US Ambassador’s residence Winfield House, near Regent’s Park, where Mr Trump is staying during the visit. The US ambassador's residence was purchased by world-famous heiress Barbara Hutton in the Thirties who was concerned about threats to kidnap her son and was impressed with the security the property offered her family.
The main demonstration against the president is scheduled for tomorrow when as many as 250,000 protesters – including a raft of senior Labour MPs - are due to march from Trafalgar Square to Downing Street.
After his arrival, Mr Trump inspected a Guard of Honour with Prince Charles at Buckingham Palace. The three-day state visit will include lunch with the Queen and a State Banquet at Buckingham Palace, as well as business meetings with the Prime Minister and the Duke of York, before travelling to Portsmouth to mark the 75th anniversary of the D-Day landings
A bomb-proof limousine dubbed ‘The Beast’ will be used to chauffeur Mr Trump during his visit.
The conspicuous eight-ton vehicle - officially known as the Cadillac Presidential State Car - was ferried across the Atlantic Ocean by Air Force transport aircraft.
Mr Trump’s heavyweight seven-seater boasts armour-plated doors which are eight inches thick, the same weight as those on a Boeing 747 jet, and designed to completely seal up the passenger cabin in the wake of a chemical or biological attack.
The president also has at his side at all times a White House doctor and one of five rotating military aides who carry the nuclear “football” - equipped with communication tools and a book with prepared war plans.
A panic button and an internal oxygen supply have also been installed in the rear compartment of the vehicle.
The $2million (£1.5 million) bulletproof limo, which reportedly does around 5mpg, also carries an armoury of weapons including machine guns, pump-action shotguns and tear gas launchers.
It also features Kevlar-reinforced, bullet-proof tyres, night vision cameras, GPS tracking, a steel-reinforced chassis and a firefighting system in the boot compartment.
A satellite phone installed in the vehicle enables communication to be maintained from anywhere in the world.
An enormous surveillance operation will be running in the background throughout Mr Trump’s trip to identify any potential threats to the president.
The secret service, Met Police counter terrorism and firearms teams, along with GCHQ will all be working together to protect Mr Trump.
The protests will feature a return of the giant 20ft inflatable nappy-wearing Donald Trump baby blimp, which has been given the go-ahead by Mayor of London Sadiq Khan and the Civil Aviation Authority to fly over Parliament Square for two hours from 9am tomorrow.
A 16ft talking robot of Mr Trump sitting on a gold toilet is also expected to make an appearance, according to the Evening Standard.
A spokeswoman for the Stomp Trump Coalition said: “The point of these protests is to get that message across very clearly and ultimately, to disrupt Trump’s visit.
“We want him to know he’s not welcome. We also want the UK government to appreciate that, not only is a state visit for a hate-monger like Trump totally inappropriate, but that when it comes to Trumpism in our own country there is a movement of people ready to fight back.”