More than 100 firefighters and 20 fire engines attended the scene and brought the fire under control but fears remain that the building could collapse.
Although that cordon has now been reduced and now affects 20 stores as opposed to 50, fears have grown among retailers about a slump in profits.
A statement from the London fire brigade this morning said that ten fire engines and around 50 firefighters remain at the scene and have managed to stop the blaze spreading to other buildings.
"The first, second, third and fourth floors of the five storey building have all been damaged by fire and the front of the building is unstable," a spokesperson for the fire service said.
"Crews now believe that nobody was in the building at the time the fire started."
Emergency services will continue to keep the area cordoned off throughout the day while they work to ensure it is safe for the public to return, prompting concern that many shops will be affected by a reduction in revenue.
In an uncertain time for consumer confidence and after a bad new year period for retailers, any reduction in spending on the capital's most lucrative street of shops is likely to have an impact on profits.
"It will certainly have an impact," said a spokesman for New West End company, a business-led partnership covering Bond Street, Oxford Street and Regent Street.
"Oxford Street is the busiest in the country - it takes millions of pounds each day – but the rest of Oxford Street is open for business as usual."
The spokesman added that the potential impact of the fire would be negated somewhat by the fact that many of the shops were high-street chains and shoppers would be able to buy their goods elsewhere in London.
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