Greta Thunberg criticises Boris Johnson at Youth4Climate

The Swedish climate activist, Greta Thunberg, used her speech at the Youth4Climate conference in Milan to mock the words of world leaders, including UK PM Boris Johnson.

The 18-year-old quoted Mr Johnson, to highlight what she called the "empty words and promises" of politicians.

Later in the speech, she urged people not to give up hope, saying that change is "not only possible, but urgently necessary".