It's bad news for mourners hoping to view the Queen's coffin.
The queue to see Queen Elizabeth's coffin at Westminster Hall already holds thousands of mourners but the Mirror has reported it could be shut off at "some point" this weekend.
The late Queen has been lying-in-state since 5pm Wednesday (4am Thursday NZT) and will stay at Westminster Hall until 6.30am on Monday (5.30pm Monday NZT) but the queue could be shut off as early as Saturday as it takes so long to get to the front.
Speaking to the Daily Mail, Culture Secretary Michelle Donelan said that the wait in the queue could reach 30 hours while government sources confirmed to the publication they are looking at closing the line at "some point" over the weekend.
Reaching 11km and expected to grow by at least another 4km the queue is expected to see over 750,000 people move through it.
Reports have already revealed some members of the public have been waiting at least nine hours as they snake across a bridge and along the south bank of the River Thames beyond Tower Bridge.
Despite the lengthy wait times, people said they didn't mind, and authorities have arranged portable toilets and other facilities to make the slog bearable.
"I'm glad there was a queue, because that gave us time to see what was ahead of us, prepared us and absorbed the whole atmosphere," health care professional Nimisha Maroo told AP. "I wouldn't have liked it if I'd had to just rush through."
It comes after the UK Government issued guidance for mourners on what to expect what you can and can't bring along with you, and how to behave.
Visitors will go through airport-style security and there are strict rules around what you can bring with you. Only small bags - smaller than 40cm x 30xm x 20cm - are allowed. If you have a larger bag, you will have to leave it at the bag drop facility, but you will leave your belongings there at your own risk as space is not guaranteed.
Banned items include:
• Flasks or water bottles, except clear water bottles. Clear water bottles must be emptied of their contents before you enter the security search point at the Palace of Westminster.
• Food and liquid of any kind. Any food or liquids must be consumed in the queue or disposed of before you enter the security search point at the Palace of Westminster.
• Flowers or other tribute items (including candles, soft toys and photographs). These items can't be taken into or left in the Palace of Westminster. Floral tributes only should be taken to the dedicated floral tribute area in Green Park.
• Sharp items, including knives, Swiss Army knives, scissors, cutlery and screwdrivers.
• Personal defence equipment or any object that could be used as a weapon and/or compromise public safety, including personal defence sprays.
• Paint sprays, padlocks, chains, climbing gear, and dangerous or hazardous items.
• Fireworks, smoke canisters, air horns, flares, whistles, laser devices, and other items that could be used to cause a disturbance or noise.
Banners, placards, flags, advertising or marketing messages, and other similar items that could be used to cause a disturbance.
There's also a strict code of conduct for viewing the Queen's coffin, with a ban on:
Filming, taking photos, or using mobile phones or other handheld devices in the security search area and the Palace of Westminster.
Bringing or setting up gazebos or tents.
Lighting barbecues or fires.
Attempting to queue on behalf of others or ask others to queue on your behalf. Only those given wristbands at the end of the queue will be able to stay in the queue.
Leaving personal items unattended in the queue. If you leave bags or other items unattended they will be removed and may be destroyed.