For those intent on joining the queue on Friday morning the message that flashed up on the electronic screen became even more disconcerting than the prospect of spending most of the day trundling along the line until eventually reaching the Palace of Westminster.
In capital letters it read: "Lying in state queue is currently paused. Please do not attempt to join until it resumes."
The message from the government's Culture Department soon got around that the park was at capacity and would likely pause for six hours.
Those entering the park were left with a "stick or twist" choice about carrying on.
Marshals overseeing the line said it stopped moving for about half an hour in the morning but resumed its slow march thereafter to Westminster Hall.
They included Otiliah Nyamande, 71, who travelled from Zimbabwe to see the queen lying in state.
“It is a privilege to see the queen. When she became queen I was 2 years old. Now I know I am old,” she said, fiddling with her scarf as the golden leaves crunched under foot.
“Whatever is going to happen I am going to wait. I have water but I will look for something to eat," said Ms Nyamande, who is staying with family in London.
“She was a leader from God. I love my queen and I want to see her. I will wait and see how I manage because I am old. I am 71.
"I thought I would never get the chance to see the queen,” she says, breaking out into the old version of the British national anthem, God Save the Queen.
Kate Wright was among others who had heard the queue was paused, but thought she would take a chance and come to try to join the line anyway. She set off from Chichester with her eight year-old son and husband Ian.
"You could see all the emotion on TV and I wanted to be part of it. I have been crying for days. I just felt this overwhelming feeling that I needed to be here," she said.
"I wanted to just come. We were well prepared to get the train home if we had to."
Others came on their own, brimming with energy and well prepared for a long wait.
Deborah Fox, 63, from Kent, left Canterbury at 11am to reach London. She heard the queue was paused just as she was boarding the train.
“I thought shall I take a leap of faith or not. I got this far, but I anticipate the 6 hour pause and the 14 hour queue might have an impact on what I am doing. But I am determined," she said, shortly after joining the queue at around 1pm.
“She has been part of my life for all my life. So part of it in terms of she has been there, a constant beacon to the world.
“I know have the opportunity. I am not bound by work or any commitments and I thought if I don’t grab the opportunity, I might regret it," said Ms Fox.
“I have snacks. I must admit I have eaten half of them already. But I feel I am fuelled up for the next 14 hours.
"My children are concerned I am on my own and I said I am not on my own."
Sharon Robinson, 60, who is from London originally but now lives on the south coast, also travelled to London alone to see the queen.
“My son told me the queue had been paused when I was on the train. I thought oh dear but I have committed now, so I am going to go," she said.
“I am not a massive royalist but I have always followed the royal family. And my mother was a great fan of the queen, which is partly why I am coming today. We are a family from London, my mother loved the queen and I just felt it was the right thing to do."
Gayle Farrell-Lymer, 47, who was clutching a plastic bag filled with bottled of water, a coke, a power bank to charge her phone, was 45 minutes into her long wait, but at peace with the thought of the journey ahead.
She travelled to Dundee from her home in Birmingham to see the queen's cortege passing through the city and wanted to see her lying in state.
“We have been here about 40 minutes since we came into the park. It’s a long walk round all the rails. We came from Birmingham and when we were on the train we heard the news they had closed the gates. We thought we are already on the way, we’re going and that’s it.
“As we were walking back there one of the marshals said to us don’t rush, it’s open again.
“I suppose it was just to allow a bit of the build-up to go down. It’s been OK to be fair. It's moving quite fast."
She said the queen was a "wonderful lady".
"You don’t realise when you are young just how important she was. As you get older and you appreciate things more you really see how much she has done and achieved in life, how the legacy will live on.
“We lived through it, all of the time she was there.
“We are glad to be here today and glad they opened up the gates. I think we would have waited to see if they opened again anyway. We had planned for the long haul.
“We will just see how we go and we will get to see some lovely sites on the day. We will get to see the big sites at night time. I have never seen them in the dark before.”
Mourners were told not to attempt to join until it reopens again later. Waiting times were 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."
But marshals said the queue only stopped moving for 30 minutes.
"The queue hasn’t been paused. We were paused here for about half an hour earlier, but we seem to have, whether there was a miscommunication or what we don’t know,” said the former soldier, who asked not to be named as he interrupted by the sound of his ringtone, set to the British Grenadiers, the regimental march.
“We were straight back into it.”
The queue snaked its way all the way from Southwark Park in central south-east London to Westminster Hall, where the monarch is lying in state.
The accessible queue was also very busy by late morning, officials said.
"Time slots for this afternoon have now filled up. There are long wait times Please consider this before making your way to the accessible queue," the culture department tweeted.
The queue, which was paused at 9.50am, was about eight kilometres long at the time, according to the culture department's live queue tracker.
About 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.
What are the rules for attending the queen's lying in state?
The government urged people to “dress appropriately for the occasion to pay your respects”, banning clothes “with political or offensive slogans”.
“Please respect the dignity of this event and behave appropriately. You should remain silent while inside the Palace of Westminster,” it added.
Queue-jumpers and anyone drunk will be removed by stewards and police patrolling the lines.
Visitors will also face airport-style security checks, with tight restrictions on what can be taken in.
Flowers, tributes, candles, flags, photos, hampers, sleeping bags, blankets, folding chairs and camping equipment are all banned, with only one small bag with a simple opening or zip permitted for each person.
What to bring to Queen's lying in state?
Official guidance suggests that people should bring suitable clothing for the weather, food and drinks to have while queuing, a portable power bank for their mobile phone and any essential medication.
Only bags smaller than 40 centimetres by 30cm by 20cm will be allowed into the hall.
Larger bags can be left at the bag drop-off centre, but capacity is limited and waiting for a space will increase people’s queuing time, the guidelines stated.
Flasks or water bottles, except clear water bottles that must be emptied of their contents before the security search point, are prohibited inside, as are weapons, whistles, smoke canisters, air-horns and similar items.
The queen’s coffin is guarded around the clock by units from the Royal Company of Archers and Gentlemen at Arms, the Yeomen of the Guard, at Westminster Hall.