The service began broadcasting globally via the BBC News website at 5pm on Wednesday, when the doors of Westminster Hall opened to the public.
Mourners could be seen tearful as they filed solemnly past the coffin and paid their respects.
The number of people viewing the dedicated stream quickly rose to about 20,000 and remained there for much of the first hour of broadcast.
The service is also available in the UK on the iPlayer, BBC Parliament and the red button until the Queen’s funeral.
Up to 400,000 people are expected to brave a 12-hour wait on the banks of the Thames to pay their respects to the Queen as she lies in state in Westminster ahead of her funeral on Monday.
Thousands of mourners are continuing to join the miles-long queue to pay their respects to the Queen as she lies in state at Westminster Hall.
Many have queued overnight for the chance to file past the monarch’s coffin after it was handed to the care of the nation on Wednesday afternoon.
By 8am on Thursday, the queue was around 2.6 miles long and stretched to Borough Market.
The coffin, which sits on a catafalque and is draped with a Royal Standard, continues to be guarded at all hours by units from the Sovereign’s Bodyguard, the Household Division or Yeoman Warders of the Tower of London.
The Government has issued guidance about what can be carried into the hall, bathroom facilities for those in the queue and the risk of having to wait through the night.
As hunders of people of all ages filed past the coffin of the long-reigning monarch, many wiped their eyes with tissues.