The UK has left the European Union after 47 years of membership.
A picture of Elizabeth Tower was projected onto 10 Downing Road, and pre-recorded bongs from Large Ben had been performed at 23:00 GMT.
Prime Minister Boris Johnson hailed a “new daybreak” for the UK, as European leaders warn of a troublesome battle forward in commerce talks.
Professional-Brexit campaigners held a celebration rally in close by Parliament Sq., which was lined with Union flags.