Why is Liz Truss ruling out a US trade deal?

Liz Truss is in New York today on her first foreign visit as prime minister. On the flight across the Atlantic, Truss said that a trade deal with the United States was unlikely in the 'short to medium term'. Why has the PM, who was so vocal about a free trade agreement with the US in the 2019 election, changed her tune? 

Cindy Yu speaks to James Forsyth and Katy Balls. 

Produced by Cindy Yu and Max Jeffery.