The Foreign Secretary and former chancellor were also pushed to clarify whether they would deploy British troops to Ukraine and on how they felt about offering Boris Johnson a seat in their cabinets.
Here are the key points raised during the hour-long face-off aired by BBC News, and hosted in the Staffordshire city of Stoke-on-Trent.
– Mr Sunak accused Ms Truss of pursuing a closer relationship with China, something the Foreign Secretary vehemently disputed
Mr Sunak said: “There was a time when Liz was talking about having a golden era of relationships with China and the mission there was talking about having deeper collaboration with things like food security and technology.
“But what we do need to do is acknowledge that China is a threat to our national security, it’s a threat to our economic security.”
He added that under his tenure as chancellor, the Government tabled the National Security Investment Bill, which gives the UK the power to “protect ourselves against countries like China who are trying to infiltrate our companies and steal our technology”.
Ms Truss interjected, saying: “Rishi, I challenged you on the debate last week.
“As recently as a month ago you were pushing for closer trade relationships with China.”
She accused Mr Sunak’s former department, the Treasury, of harbouring a desire for “closer economic relations” with China, while the Foreign Office has taken “the toughest stance” with the country including