A newly-crowned King Charles III leaves Westminster Abbey. (AP)

Tens of thousands of people packed the streets of London on Saturday to witness the once-in-a-generation event of King Charles III's coronation.

Britain's new monarch was greeted with a sea of red, white and blue as admirers waved Union Flags during the procession ceremony from Buckingham Palace to Westminster Abbey.

However, not everyone was feeling so jubilant about the occasion, with the Metropolitan Police arresting a number of anti-monarchist protesters, confiscating a number of placards reading "Not my King".

Whatever your allegiance, Saturday 6 May was a rare moment in modern history – the UK's first coronation since 1953.

Here, Yahoo News UK takes a look at some of the highlights and some of the moments you may have missed.

Anti-monarchy protesters arrested

Police arrested several members of anti-monarchist group Republic. (Alamy Live News)

The Metropolitan Police came under heavy criticism after a number of anti-monarchist protesters were arrested ahead of the King's procession.