Boris is not going to resign , he just doesn't have the moral compass to actually give a rats ass.
the only way he would go is of he becomes toxic enough to voters for the Tories to kick him out in fear of their seats.

the issue now is the Tories would find it hard to kick out Boris over this without also kicking out the obvious successor in Sunak - and NOBODY else in the Tory party is polling well AT ALL