Britons travelling in Central London on the day of the funeral are advised to reschedule their journey if possible. The capital is likely to be most affected due to road closures and huge crowds.
Parts of central London are closed to normal traffic and bus routes in some areas of the capital are likely to be affected.
The Tube is running as normal but some station access points will be closed or may exit only.
Many roads between Windsor and London will be closed as the Queen makes her final journey.
Transport for London emailed passengers to warn against driving through central London on September 19.
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It said: “You should avoid driving (affected) areas during this time. If you have to drive, then please check before you travel, allow extra time for your journey, use alternative routes and expect long delays.
“Bus routes in central, west and southwest London will also be severely affected with many routes on diversion or stopping short of their destinations.”
It added that some roads may reopen on Monday evening, depending on the advice of police and other authorities.
Some public transport operators around the country will be running a reduced schedule today to allow colleagues to pay respect to the Queen.
Air traffic restrictions are in place at Heathrow as normally flights arrive over central London to the major UK airport.
Around 200 flights have been cancelled to and from Heathrow Airport to avoid disrupting the funeral with plane noise.
Heathrow said: “As a mark of respect for the solemnity of this sad and unique occasion, operations at the airport will be subject to alterations to avoid noise disturbance during the state funeral.
There will be four periods of time where flights are affected which are all during key moments of the funeral day.
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British Airways has cancelled around 100 flights to and from Heathrow on Monday and Virgin Atlantic has cancelled four flights.
Flights from London City Airport won’t fly out over Westminster during the state funeral.
A spokesperson said: “During the state funeral, London City flights will not fly over Westminster out of respect for the funeral service for Her Majesty the Queen.
“We are working closely with our airlines to operate a normal schedule on the day and if there are any changes to flight times, passengers will be notified by their airlines.”
Crowds at railway stations are expected to be at their busiest on Monday afternoon, as people leave the capital after the funeral.
Passengers may have a more comfortable journey if they delay their journey until later on in the day.
Great Western Railway has added an hourly link from London to Swindon, Bath and Bristol on Monday night.
Welfare trains will be stationed at some stations including London Marylebone, St Pancras and King’s Cross where people will be able to rest comfortably.