Eighteen people have been arrested and three police officers injured after anti-lockdown protests in central London.
Demonstrators made their way through the city with banners and placards, calling for "freedom" and an end to COVID-19 restrictions.
At least two people were led away in handcuffs from Trafalgar Square, while there was also some disruption on Westminster Bridge as officers tried to disperse crowds.
The Metropolitan Police said three officers suffered minor injuries following clashes with protesters.
Demonstrators called for an end to the "tyranny" of new rules amid the pandemic and voiced their opposition to vaccines.
The protests were "complex" and at "various locations across central London", police commander Ade Adelekan said.
While the "vast majority" of people listened to advice and left the area, a small minority became "obstructive" and "deliberately ignored instructions", he added.
Organisers did not take "reasonable steps to keep protesters safe" and therefore "voided their risk assessment", Mr Adelekan said.
"One demonstration in particular attracted a large number of protesters and I became increasingly concerned that those in the crowd were not maintaining social distancing," he added.
The crowds were dispersed in the "interests of public safety", police said.
People were detained for breaching coronavirus regulations, assaulting an emergency service worker, violent disorder and for being wanted.
In a 6pm update, the Metropolitan Police said all crowds had been dispersed and 18 arrests had been made.
Police were initially deployed outside Buckingham Palace as crowds of protesters gathered on the steps of the Queen Victoria memorial, before making their way to Trafalgar Square.
Under current regulations, no one can participate in an outdoor gathering of more than six people unless certain exemptions apply.
Earlier on Saturday, around 50 people gathered in Parliament Square for a protest organised by the Stop Trump Coalition.
A pantomime cow and a group of chlorinated chickens were among demonstrators who turned out to protest against a proposed trade deal between Britain and the US.