In this special edition of Talking Politics, Robert Peston meets ex-Civil Service chief Simon Case. Sir Simon served four prime ministers as Civil Service chief before standing down as Cabinet secretary in December.

In a wide-ranging conversation about the prime minister's plans to significantly invest in the UK's defence capability, including its nuclear deterrent, Sir Simon warned that the UK and West "better be ready" for a Chinese invasion of Taiwan. Plus:

• The future of America in Europe
• The struggle of government spending trade-offs
• The infamous Truss letter: His side of the story 

You can watch or listen to more episodes of Talking Politics on ITVX, YouTube or on your favourite podcast platform. Got a question for Robert and the team? Email us on [email protected] or comment on our social media posts and we’ll feature them in our Q&A special episodes.