Mourners are facing a five-mile, 30-hour queue to see the late Queen lying in state.
Her Majesty will lie in state at Westminster Hall in the Palace of Westminster, also known as Parliament, from 5pm on Wednesday.
Hardy royalists have already joined the line on the opposite side of the River Thames - some having been there for almost three days.
When people begin filing over Lambeth Bridge and into Westminster Hall to pay their respects to the late monarch, it is said the queue will be in continuous motion.
This means people won't be afforded the opportunity to sit down and put their feet up.
Queuers have been sharing tips on how to cope with the marathon lines, and one man - an Army veteran of 22 years - said his secret was: "It's an old trick. Literally just rocking back and forth on your heels, sips of water some barley sugar sweets and then crack on."
For those who find themselves standing for long periods today, the medical advice is to keep moving.
Ryan Balmes, an Atlanta-based therapist and spokesman for the American Physical Therapy Association.
"I always say your best posture is your next posture—meaning, you don’t want to be in a certain position for long periods of time," he told Vice.
His advice to patients who have to stand for hours for work is to set alarms on their phones or smart watches, reminding them to "get moving in a different direction".
Going equipped with the right footwear is also vital, according to Canada’s Occupational Health Clinics for Ontario Workers Inc, who warn against wearing flat soles for long periods of standing.
They recommend your heel should be elevated by at least a quarter of an inch and should be less than two inches to reduce soreness.
People are also advised to stretch when they can.
Healthline.com recommends these two exercises:
Calf raises help pump blood out of the foot (where it has pooled while you were standing) and back to the body.
- Stand tall on the edge of a step or platform, with your abdominal muscles pulled in.
- Secure the balls of your feet firmly on the step with your heels hanging over the edge.
- Raise your heels a few inches above the step as you stand on your tiptoes, and hold for a second.
- Lower your heels back to even with the platform.
- Repeat 10 times.
The runner’s stretch.
- Face a wall and place your hands against it.
- Extend one leg behind your body.
- Push your heel to the floor as far as it will go.
- Hold for a moment to feel the stretch and then switch sides.
- Repeat three times on each leg.
