Fire has destroyed much of the National Motorcycle Museum near Birmingham, ruining 650 vintage machines and leaving 60% of the building a blackened shell.
Many of the 650 bikes destroyed were unique
Investigators are at the scene on Wednesday to begin an inquiry into the cause of the fire.
The value of the destroyed bikes is put at £8m, but many of the machines are irreplacable.
Staff and conference delegates at a business conference at the museum at Bickenhill, near Birmingham International Airport, saved some of the 900 bikes after fire broke out at around 1700 BST Tuesday.
More than 120 firefighters tackled the fire which could be seen for 15 miles
The bikes destroyed in the collection traced the history of the British
motorcycle industry and many of the museum's rarest exhibits were among those lost.
Exhibits included BSA Gold Stars, Sunbeam Twins, DMW Hornets and Triumph racers.
But museum bosses have vowed that the museum will be rebuilt and hopes remain that some of the damaged bikes could be saved.
Neil Payne, competition and demonstrations manager at the museum, said: "I am sure that it will rise, like the proverbial phoenix, from the ashes.
"At the moment we do not know whether the bikes are destroyed beyond redemption.
"We keep thinking it's a bad dream and we are going to wake up.
"This is a huge loss to British heritage."
Staff at the museum were said to be "absolutely devastated".
A museum spokesman said: "Over 300 of the exhibits in the museum have been saved.
"Sadly, three of the museum's five exhibit halls have been destroyed along
with their exhibits.
"A full assessment of the damage is being undertaken with a view to getting
operations under way again as soon as possible.
"Many irreplaceable machines will have been damaged in the fire, but they
will be restored once again, to their original showroom condition."
The museum was home to more than 900 vintage machines.
Owner Roy Richards started collecting the bikes in the 1970s and the museum opened in 1984 with an initial collection of 350 machines.
It became one of the biggest motorcycle museums in the world and attracted about 250,000 visitors a year. It was also a conference centre.
Mr Richards told BBC Midlands Today: "It is a devastating loss, not just to me, but for the country as a whole."
Staff and conference delegates helped rescue bikes
Exhibitor Neil Payne told the BBC: "There are so many unique, priceless, irreplaceable machines that are lost. It is absolutely devastating.
"The museum and indeed the country has lost some unique machines from British motorcycling history."
Firefighters remained at the scene throughout the night damping down the scene in preparation for investigations into the cause of the fire begin.
It is thought to have started at the rear of the building near a lift shaft.
At its height, there were big delays on the A45 between Birmingham and Coventry and smoke was drifting across the nearby M42.
The traffic problems made it difficult for the fleets of fire engines trying to get to the scene.
Three of the five exhibition halls were destroyed
The Department of Trade and Industry (DTI) minister Jacqui Smith had been due to attend a conference at the museum on Tuesday evening.
A DTI spokeswoman said on Tuesday: "She was expected to attend the Manufacturing Advisory Service dinner which was cancelled because of the fire.
"She was informed long before she was due to be there that it would not be taking place.
"She will be contacting the museum to pass on her condolences."