After months of preparations, the concrete skeletons of Leicester City Council's crumbling former New Walk Centre headquarters will be razed to the ground on Sunday.
The two towers, one 13 storeys and one eight, will take only 10 or so seconds to disappear in a huge cloud of dust.
The buildings will be at the centre of a 150 metre exclusion zone, which will be in place from 6am to 6pm to allow for a major clean-up operation afterwards.
Some 400 nearby homes and businesses will be evacuated - before explosive charges and gravity pull down the 16,000 tonnes of concrete which are all that remain of the old council offices, after they have been stripped bare.
The high security operation, costing some £3.5 million, is being carried out by demolition firm DSM.
Experts have pre-weakened the towers and say they should collapse within their own footprint - largely into the complex's former underground car park - preventing damage to nearby premises
The nearest building to the towers is the council's Phoenix House, which stands some 15 metres away.
DSM contracts manager Billy Young said: "Our overarching aim on the day is safety.
"In 15 years I have only ever broken one window.
"I aim to keep that record up.
"There will be no big bang. There will be a series of detonations for five-and-a-half seconds.
"It will look like nothing has happened at first. That's when most people assume something has gone wrong.
"If they are taking pictures they turn away and miss it, because then, five-and-a-half seconds after that, it will start to collapse.
"All you will see after the first few floors falling is a big cloud of dust."
No specific time has been given for the demolition, but the process will be millisecond specific.
The entire operation can be aborted up to the final moment before the demolition, which can only be triggered by three DSM staff.
DSM will record the demolition with seven cameras and possibly a drone.
It is hoped the police helicopter can be used to scan the buildings with heat imaging cameras to make sure they are clear.
The cordon around the site will be manned by police and security staff to keep people out.
Should there be any cause to abort the demolition, DSM says it can reset the process within five minutes and start again.
A siren will sound five minutes before the demolition - described as a controlled implosion, or "blow down".
Officials have advised members of the public not to gather around the edges of a tightly monitored 150 metre exclusion zone around the towers.
No public viewing arrangements have been made for the event.
However it is still expected hundreds, if not thousands, of spectators will be jockeying for position to get a good view of the towers falling.
City mayor Sir Peter Soulsby said: "I have spent a lot of time in these buildings over the years, an awful lot of time.
"I certainly won't be shedding any tears over them and I don't think anyone else will.
"It is the single largest demolition project this city has seen, and naturally there will be some excitement.
"I will be resisting the suggestions that have been made by some people that I should watch the towers come down from inside.
"There will inevitably be some disruption with an operation of this scale and we apologise for that, but the method of demolition we have chosen is the fastest."
Perimeter fencing will be in place to ensure debris and dust are largely contained within the demolition site.
The whole operation will be monitored closely by the Health and Safety Executive, which is responsible for overseeing the process and ensuring it meets stringent safety conditions.
The exact time of the demolition will be decided by contractors DSM on the day itself, once all the relevant safety checks and preparations have been carried out.
Displaced businesses people and residents in the immediate area will be invited to go to a specially set up respite area at Leicester Tigers' Welford Road ground. There they will able to watch the demolition on a specially set-up big screen feed.
THE EXCLUSION ZONE
The exclusion zone area is bordered by Upper Brown Street, Chancery Street, part of Pocklington's Walk, part of Market Street including the Fenwick store, Wellington Street, Park Street, and the bottom section of New Walk from approximately Holy Cross Church.
It will extend across New Walk to King Street at its junction with Marquis Street, before crossing Duke Street, Mill Street, and Welford Road near Bannatyne's gym.
It will continue behind buildings on the western side of Welford Road, York Road and behind Newarke Street car park, which will be closed for the demolition.
TRAFFIC
Drivers heading into Leicester this weekend have been warned there could be extensive disruption caused by the demolition operation
The exclusion zone around the demolition site will mean numerous road closures, parking restrictions and diversions for the duration of the demolition.
Parking on streets within the exclusion zone will also be suspended from 6pm tonight to ensure no cars are left there.
Some bus services will also be diverted for the duration of the demolition.
The Southgates Underpass, Newarke Street and Welford Road will be closed to all traffic for the day, along with all other roads in the exclusion zone, with southbound traffic advised to use alternative routes.
Southbound traffic using the underpass will be turned around at St Nicholas Circle and directed clockwise round the inner ring road.
Traffic bound for Welford Road will be signposted instead clockwise along Vaughan Way, Burleys Way, St Matthews Way, St Georges Way, Waterloo Way and Tigers Way.
Drivers leaving the Highcross shopping centre will not be able to use Southgates, but instead will be turned around via St Nicholas Circle and directed onto the inner ring road or Hinckley Road.
Newarke Street car park will be closed throughout the demolition, with access to the NCP car park at Duke Street via Regent Road only.
BUSES
Bus firm Arriva has published detail of how the exclusion zone will affect its services.
Arriva Services 48A, 49A, 84, 85, 86, 87 towards the city centre will go down Oxford St then Southgates, Vaughan Way, Abbey Street then to either into St Margaret's Bus Station or into city centre.
Services 47A, 49A, 84, 85, 86, 87 leaving the city centre will pass down Charles Street/Rutland Street then Charles Street, St George's Way, Waterloo Way, Regent Road, Welford Road then to their normal routes.
Arriva has apologised for any inconvenience caused to passengers.
WHAT NEXT?
Once the nearby premises have been cleaned of dust and assessed for any damage the exclusion zone has been lifted the process of removing the rubble will begin.
The site should be clear by May.
City mayor Sir Peter Soulsby says the council is just weeks away from announcing what will replace the towers.
He has promised a mixed-use development, likely to be largely made up of new office accommodation.
The council moved out of New Walk in the summer with most of the 1,200 staff based there transferring to the renovated Attenborough House - now called City Hall - in Charles Street.
Others moved into smaller council complexes around the city centre.
The council had to leave the New Walk Centre, its base for more than 40 years, because structural engineers said the buildings had become unsafe.
The council's insurers therefore said there were no longer willing to cover the premises.
More information on arrangements for the demolition is available at: www.leicester.gov.uk/newwalkcentre
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