US Democrats begin a formal impeachment enquiry

The Democratic party will take the first step towards impeaching Donald Trump over claims that he used the withholding of aid to Ukraine to try to force the Ukrainian government to investigate Joe Biden, his possible rival in next year's election. The House Speaker Nancy Pelosi has until now been resisting calls for impeachment proceedings, believing that voters won't like it when it comes to the election.

Also on the programme: a new IPCC report has been released, telling governments what they should do to protect oceans and the world's icy regions. We meet one of the authors. We also ask what actions are left open for the UK Prime Minister Boris Johnson following yesterday's verdict of the Supreme Court that his suspension of parliament was unlawful.

(Photo: House Speaker Nancy Pelosi Credit: Wilson/Getty Images)