Stewart accused of 'Project Fear in overdrive'published at 13:42 British Summer Time 10 June 2019
The World at One
BBC Radio 4
The next caller asks about the possibility of introducing zero tariffs after Brexit.
"If you went zero tariffs on agricultural products you would get cheaper beef and cheaper lamb," replies Mr Stewart.
However, he says that would be "the end of the farming industry in the UK".
"You could also import cheaper cars which would be good for consumer but the UK car industry would be wiped out," he says.
The caller describes this reply as "Project Fear in overdrive".