Private firms will be providing physical security and crowd control measures ahead of the Queen’s State Funeral next Monday.
Staff are installing barriers, temporary flooring, queuing systems and other services to deal with the anticipated huge influx of people into London.
Portable toilets along the route of the queue – which could number 750,000 – into Westminster Hall where the Queen will lie in state from Wednesday evening when she is returned by the RAF to London from Scotland.
She died at her Balmoral estate last Thursday aged 96.
Brentwood-based Headline Security is one firm involved in the preparations for the State Funeral and period of national mourning.
Among the services the family-run company offers is for crowd management.
A spokesman for UKCMA-accredited Headline confirmed: “We’re definitely involved.”
According to one report, Wise Security in Dartford is also involved in the preparations. SJUK approached the the company for comment.
A marquee and armed police can be seen at the entrance to Cornwall Gardens with several police and emergency service vehicles parked across the road, according to reports today.
Security staff by Victoria Tower Gardens told the Press Association news agency that crowds are expected to swell ahead of Wednesday afternoon.
The queue is likely to snake for miles, they said, potentially all the way along the river to Tower Bridge.
People will not be allowed to camp and will be given numbered wristbands to indicate their place in the queue so they are able to leave and come back, security staff said.
On Monday morning, pedestrians were walking freely up and down the route without anyone appearing to have arrived early to queue.
The atmosphere has been calm as dozens of broadcasters set up cameras to film along the south side of the river with the Palace of Westminster in the background.
People will be able to queue 24 hours a day until 6.30am on Monday for the Queen’s lying in state.