ITV News reporter Rachael Younger met one woman whose already camping to pay her respects to the Queen
People have been warned not to wait or camp along the route thousands are expected to queue to see the Queen’s coffin Lying in State.
Her Majesty will be taken from Buckingham Palace to Westminster Hall, where members of the public will be allowed to pay respectful tribute.
On Wednesday afternoon, the monarch’s coffin, adorned with the Imperial State Crown, will be transported on a gun carriage of The King’s Troop Royal Horse Artillery.
King Charles III, members of the royal family and senior staff of the late Queen's households will walk slowly behind in a dignified silence without music along a route that will take 38 minutes.
The ceremonial procession will move along The Mall, Horse Guards Road, across Horse Guards Parade, onto Whitehall and into the Palace of Westminster after 2.22pm.
Viewing areas along the route with limited capacity will open at 11am on the day, with people admitted in order of arrival time amid expected large queues, the Department for Digital, Culture, Media and Sport (DCMS) said.
If a person leaves the area their readmission cannot be guaranteed, the DCMS has warned.
The Queen’s coffin will be flown from Edinburgh to RAF Northolt in west London on Tuesday.
Some mourners said they were already preparing to queue in central London on Monday - two nights before the public is being invited to see the Queen Lying in State.
The DCMS warned, “Please do not wait or camp in advance of the processional day.
“If you camp before this time you may be asked to move on.”
People are also advised to bring with them suitable clothing for any weather conditions, food and drink and appropriate footwear.
Tents, gazebos or camping gear, barbecues and equipment for fires and alcohol are prohibited.
Mourners must keep noise to a minimum when the procession passes them and have been told to behave appropriately, dispose of litter and follow the instructions of police and stewards or face being asked to leave.
There will also be large screens at Hyde Park where those who cannot access viewing sites can watch the procession, which will also be broadcast on ITV News.
The Archbishop of Canterbury will conduct a short service following the coffin’s arrival.