Demonstrators set off from at Hyde Park Corner in London, Saturday Sept. 9, 2017, protesting Britain’s plans to withdraw from the European Union. (Photo: John Stillwell/PA via AP)

The march was aimed to "unite, rethink and reject" the Conservative government's plan to implement Brexit by 2019, creating a mechanism to end the supremacy of EU law in the UK. Parliament is expected to vote Monday on a repeal bill which aims to ensure 12,000 EU laws will no longer apply in the UK. The Theresa May’s administration expects to win the vote despite it may face opposition from pro-Europe protesters.