Westminster Hall has re-opened after a two hour break, enabling mourners to pay
their respects to the Queen Mother, House of Commons authorities said.
Members of the public were able to visit the hall until 6 a.m. when it was closed for two hours before re-opening at 8 a.m.
Crowds continued to stream past the Queen Mother's coffin long after Big Ben had chimed midnight.
The queue outside Westminster Hall stretched for more than 300 yards with people waiting up to half an hour to get in.
As late as 2 a.m. the Hall was still packed with people waiting to sign the book of condolence, which had been moved inside.
Officials privately said the turn out had been "remarkable" and showed little sign of abating.
They said the tide of well-wishers appeared to dwindle from about 8 p.m. but then surged again shortly after 11 p.m.
The original plan had been for yesterday's public viewing to be between 2 p.m. and 6 p.m., but the many thousands wishing to attend the historic lying-in-state led to a change of strategy.
The massive public response led to extended public viewing beyond the planned 6 p.m.
The medieval hall remained open throughout the evening then the further extension was announced late last night.