Thousands of protesters took to the streets to rally against US President Donald Trump's visit to the UK.

A coalition of more than 50 organisations - including trade unions, environmental activists, anti-racism groups, and pro-Palestinian movements - assembled in central London to demonstrate against Trump's second official visit.

The group, known as the Stop Trump Coalition, began marching from Portland Place towards Whitehall at around 3 pm local time on Wednesday, September 17.

Demonstrators carried placards with slogans including 'End the genocide, Stop Trump' and 'No to racism, No to Trump'.

Authorities estimated that approximately 5,000 people took part in the march.

More than 1,600 police officers were deployed, including around 500 officers from outside London.

A spokesman for the coalition said: 'A government that will bow down to Trump and to racism is one that will open the door to fascism.'

Thames Valley Police confirmed that four individuals were arrested on suspicion of malicious communications on Tuesday, after images of Trump and convicted sex offender Jeffrey Epstein were projected onto Windsor Castle.

The visit coincided with preparations for a new UK–US technology partnership aimed at strengthening cooperation between the nations' multi-trillion-pound tech sectors.

A formal state banquet took place at 8:30 am in St George's Hall, attended by members of the Royal Family, the US delegation, and other prominent figures.

This event followed days after the Unite the Kingdom protest, during which far-left demonstrators, some reportedly associated with the group Antifa, clashed with British nationalist activists during a separate rally in London.

The demonstration reportedly attracted more than 110,000 people - though attendees claimed the number was much higher.