Tens of thousands of bodies will be dug up and moved to make way to multi-billion pound railway HS2.
A memorial service will be held on Wednesday for the 60,000 people buried near London Euston railway station whose bodies will be exhumed as part of the high-speed rail project.
Nearby residents in Camden, north London, have branded the decision "outrageous" after unsuccessfully campaigning to save the site at St James' Gardens, which was used as a burial ground from 1790 to 1853.
HS2 Ltd will excavate sections of the ground to enable it to plan the removal of the remains prior to their subsequent re-interment elsewhere.
Campaigners have strongly opposed the action, along with the cutting down of more than 500 trees in the borough to make way for the £55.7 billion railway.
Euston Station is the proposed terminus for HS2
HS2 Ltd will excavate sections of the ground to enable it to plan the removal of the remains prior to their subsequent re-interment elsewhere
Dorothea Hackman, a local church warden who helped to organise the private memorial service, said 40 people are being allowed to gather at the now closed St James' Gardens to pay respect to the people buried there.
"It's quite outrageous they are going to dig up our dead," she said.
"They shouldn't be disturbed by spurious activities like this.
"And just think of the detrimental effect removing the benefit of the trees and green space will have on the area in terms of air quality.
"There has not been destruction on this scale since the Sixties. Government has run roughshod over democracy."
Nearby residents in Camden, north London, have branded the decision "outrageous"
Local resident Marian Kamlish, 92, said: "In times of austerity, this vanity project is an insult to those in the NHS, in education, in the fire services and the police force, all suffering cuts while this rich man's railway sucks up our money."
Several notable people are buried at St James' Gardens, including Lord George Gordon, associated with the 1779 Gordon riots; Captain Matthew Flinders, the first person to circumnavigate and name Australia; and Bill Richmond, a pioneering black boxer.
An HS2 spokesman said: "Though the former burial ground at St James' Gardens has not been in use for more than 100 years, we will ensure that we treat the site with dignity, respect and care.
"As such, we will continue to work closely with the local community, the Archbishops' Council, the local parish, Historic England and other organisations as we proceed with the next phase of the project."
In February, Parliament granted powers to build Phase 1 of the line, which is due to open in December 2026
He added that the work at Euston will triple the number of seats out of the station at peak hours and create a "gateway to the capital and the nation" that the local community and travelling public can "rightly call their own".
In February, Parliament granted powers to build Phase 1 of the line, which is due to open in December 2026.
This will see trains travel at high speed between Euston and Birmingham before running on from Birmingham on the existing West Coast Main Line.
Preparatory work has begun and major construction projects are due to launch in 2018/19.
Services are expected to operate on Phase 2a from the West Midlands to Crewe in 2027, with Phase 2b from Crewe to Manchester, and Birmingham to the East Midlands and Leeds, due to open in 2033.
A burial site thought to contain 30 victims of the Plague was unearthed at Crossrail's Liverpool Street site in 2015.
Bodies supposedly dating back to the 1665 disaster were found during an excavation of the burial ground in Bedlam, London.
A worker walks past a digger in the partially completed Crossrail rail tunnel that will become Bond Street station
Lead archaeologist Jay Carver said: "This mass burial, so different to the other individual burials found in the cemetery, is very likely a reaction to a catastrophic event.
"Only closer analysis will tell if this is a plague pit from The Great Plague in 1665 but we hope this gruesome but exciting find will tell us more about the one of London's most notorious killers."
A headstone found nearby was marked "1665" and the fact the individuals appear to have been buried on the same day, suggest they were victims of The Great Plague, reports the Wharf.
The thin wooden coffins have collapsed and rotted, giving the appearance of a slumped and distorted mass grave.
The skeletons will now be analysed by osteologists from Museum of London Archaeology (MOLA), and scientific tests may reveal if bubonic plague or some other pestilence was the cause of death.