Paramedics have treated more than 700 people queueing in London to view the Queen’s lying in state.
Thousands of people are still standing in line for their turn to enter Westminster Hall, and at Saturday lunchtime the waiting time was estimated at 16.5 hours.
London Ambulance chiefs said they cared for 710 patients, between when the lying in state began and midnight on Friday, along the queuing route and surrounding areas, including Hyde Park, Whitehall and Millbank.
Some 291 patients were treated on Wednesday, of whom 17 were taken to hospital; 144 on Thursday, of whom 25 were taken to hospital, and 275 on Friday, of whom 39 were taken to hospital.
The ambulance service said most people needing care had fainted or collapsed for other reasons, resulting in head injuries.
The King and the Prince of Wales made a surprise visit on Saturday to greet mourners in the queue.
Medical chiefs warned those queuing outdoors of cold weather on Saturday night.
Director for ambulance operations Darren Farmer said: “It’s important that people joining the queue follow the advice provided on the government website, including bringing with them any regular medication, appropriate clothing, drink plenty of water and eat regularly.
“It’s likely to be cold, so it’s important people wear appropriate clothing to keep them warm.”
Temperatures are forecast to go as low as 9C overnight in London.
Government guidance advises prospective queuers they will need to stand for many hours, possibly overnight, with very little opportunity to sit down as the queue will be continuously moving.
St John Ambulance, which has also been treating people, said the most common complaints were blisters, dehydration and feeling faint.
The London Ambulance Service is planning to deploy 300 extra staff on Monday for the state funeral, and with tens of thousands of people in the capital, demand is expected to mount.
The public has been urged to “use the service wisely”, reserving 999 for serious emergencies only.
Mr Farmer urged anyone needing care to contact GPs, pharmacists or NHS 111 where possible instead.
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