Arlene Foster's Democratic Unionist Party now holds the balance of power, after elections this week. Some people have suggested that all the parties lost - but across the Irish Sea one party definitely won. Only with their votes can the Conservatives get things through the House of Commons. Which makes Arlene Foster possibly the most powerful woman in Britain. Mark Coles takes an updated look at the former first minister of Northern Ireland.

Producer Smita Patel