Stephen Flynn mocked Rishi Sunak by asking if it hurt that "Labour believes in Brexit more than he does" during Prime Minister's Questions on Wednesday.
The SNP leader at Westminster was referring to the PM's comments the yesterday that Northern Ireland was "in an unbelievably special position" and was "privileged" as it had access to both the EU and UK markets.
Sunak agreed a deal with the EU on post-Brexit trading arrangements for Northern Ireland on Monday.