How political forces in other countries will shape any future UK-EU deal.

As a younger man, Anand Menon spent a care-free summer Inter-railing around Europe. Some decades later, and now a professor of European politics, he's taking to the rails again - this time with a more specific purpose. While British ministers squabble over what they want for a post-Brexit UK, less attention is paid to the other 27 countries in the negotiations. Each can veto any long-term deal between Britain and the European Union. And each, critically, has its own politics to worry about. Professor Menon visits four European countries where politicians will face their electorates next year. What forces will decide their political survival? And how will those forces shape the EU's future relationship with the UK?

Producer: Simon Maybin.