The queue to see Queen Elizabeth II lying in state has been paused for at least six hours after reaching capacity.
Mourners have been told not to attempt to join the line until it reopens again later.
Waiting times are estimated to be at least 14 hours.
"Entry [to the queue] will be paused for at least 6 hours," Britain's culture department said on Twitter. "Please do not attempt to join the queue until it reopens."
The queue snakes its way from Southwark Park in central south-east London to Westminster Hall, where the monarch is lying in state.
"I've no sensation in my knees at all or my legs," Hyacinth Appah from London, who was in the queue, told Reuters.
"But it's been fine. Most of the people have been lovely and we've had quite a nice time."
The queue, which was paused at 9.50am, was about 8 kilometres (5 miles) long at the time, according to the culture department's live queue tracker.
Around 750,000 people are expected to file past the queen's coffin before the doors to Westminster Hall close to the public early on Monday, the day of the state funeral.