Britain and the European Union began crucial talks this week on their future trade relationship after the Brexit transition period ends Dec. 31, leaving less than ten months for the two sides to negotiate and ratify any deal. On the same day the talks began, Britain published its mandate for a trade agreement with the United States. London hopes the parallel discussions will put pressure on the EU. But as Henry Ridgwell reports from London, the European Union and the United States have their own tough demands – and Britain risks being squeezed in the middle.