Protesters chant 'down with Boris' in anti-Brexit rally outside Parliament

Demonstrators chanted 'Down with Boris' and 'F*** Farage'

Hundreds of people across the UK attended pro-European Union rallies in protest at last week’s historic referendum – despite events being officially called off over “safety fears”.

Directing their anger towards two of the leading Leave campaigners in the referendum – former London mayor Boris Johnson and Ukip leader Nigel Farage – demonstrators in London chanted “Down with Boris” and “F*** Farage”

Thousands of people were expected to attend events in cities across the UK as dissatisfaction with the decision to leave the bloc manifested itself in plans for public demonstrations. But organisers have been forced to abandon several gatherings over fears about crowd sizes.

The rally in Trafalgar Square had officially been abandoned after 50,000 people declared an interest in attending on social media – but many turned out regardless before moving down Whitehall to continue their protest outside the Houses of Parliament.

Liberal Democrat leader Tim Farron, who has vowed to campaign to take the UK back into the EU, addressed the crowd in Trafalgar Square insisting that the Brexit vote “is reversible”.

“In politics, as in life, two things are always the case for me: One, if you lose, you have the grace to accept the defeat, but you never, ever, ever give up,” Mr Farron added.

Protesters have called for independence for London if Britain leaves (PA)

“We as a community must stand together, this is reversible. The people of Britain are decent, outward-looking people. We will carry on direct campaigning.”

Hundreds of people also turned out in Cardiff for an event celebrating the European Union. It included speeches from Plaid Cymru leader Leanne Wood and racial equality activist Shazia Awan as well as a performance by Super Furry Animals frontman Gruff Rhys – who performed a song called I Love EU.

The event had already proved controversial after those behind it changed the name to apparently embrace Leave voters. It had initially been called “London stays” but was then altered to “stand together”.

Organiser Jessica Rodgers said that the event had only started with a plan to bring “20 friends together” and wasn’t prepared for “over 50,000 people who want to stand together in London”.

“We’ve tried all we can to ensure this could go ahead. However logistically it’s not possible to ensure a safe event,” wrote Ms Rodgers. “Trafalgar Square can hold 10,000 people - and that’s with security barriers, stewards, road closures, and a full contingency plan. Considering the speed with which this event has picked up, arranging everything required in time is simply not possible.

“Given this, with a heavy heart, it's too dangerous for the attendees for the event to go ahead.”

She urged supporters not to turn up to Trafalgar Square in the hope that the event would go ahead. “The logistics are not in place to ensure the safety of everybody planning to attend, and we do want the media attention around this to remain positive,” Ms Rodgers wrote.