Brexit: Northern Ireland border at the centre of negotiations

Ireland finds itself on the front line of that endlessly long-running, still-unresolved battle between harder and softer variants of Brexit.

The whole of Ireland has a population one tenth the size of the UK; Northern Ireland's population is smaller than West Yorkshire - yet it is here that the argument is being fought.

An argument that involves three borders: Britain and Northern Ireland, Northern Ireland and the Republic, and the Republic and Britain.

Newsnight's Evan Davis looks at how we solve the Brexit border problem.