A group of anti-Brexit activists rallied in front of the government offices at 10 Downing Street Monday evening, Anadolu Agency reports.
The group sang songs and danced during the rally, which also saw comedy sketches about Brexit.
Dozens of people holding EU and British flags called on the government to reverse Brexit and keep the UK in the EU.
The protest was followed by a night march to the Royal Courts of Justice via the Embankment.
The pro-EU rally and march by the Stop Brexit group came a day before the first hearing of the group Article 50 Challenge at the High Court, which will argue that Article 50 should be canceled because it does not explicitly say that parliament, and not the government, is making the decision to leave the bloc.
More anti-Brexit protests are expected Tuesday, when the House of Commons will continue to discuss the EU Withdrawal Bill.