QUEUES to see the Queen lying in state could last 12 hours and stretch for three miles.
The Whitehall chiefs in charge of logistics for the historic five-night vigil had originally estimated that 40,000 people a day would turn up.
However, they now believe the number will be far, far higher and that many people will have to queue through the night.
They estimate numbers could far exceed the 200,000 who paid their respects to the Queen Mother in 2002.
And they say it could be closer to the million mourners who filed past Pope John Paul II when he lay in state in Rome in 2005.
The route will be lined with extra portable loos and water stations to ensure the public are catered for on their way towards central London’s Westminster Hall from Wednesday.
Mourners will pass through airport-style security and only small bags are permitted.
Medics at nearby Guy’s and St Thomas’s hospitals are on standby in case those in the queue fall ill.
Planners, who have been following the Operation London Bridge protocol, have identified a park next to Tower Bridge as the starting point for the queue.
It will then move the length of the South Bank of the Thames, passing London Bridge, Blackfriars Bridge, the Globe Theatre, Tate Modern and the London Eye.
Anyone with luggage will have to stop on the route and leave it in a park by Lambeth Palace before rejoining the queue.
Mourners will cross Lambeth Bridge before turning back to enter Westminster Hall.
That will be open 24 hours a day for mourners to pass by the late monarch’s coffin, with insiders revealing people may have to wait up to 12 hours from start to finish.