What will trigger a reorg after BIP148 split? "longest chain" or "most work" ?

[Brandsen]

Question:
Assuming a split occurs after the BIP148 UASF..
What condition will trigger a reorg of the non-segwit-chain?
Is it *longest chain* or is it *most work chain* ?

[achow101]

When it comes to the blockchain, the "longest chain" means the chain that has the highest sum of the nbits (difficulty specifier in a block) fields, i.e. the chain with the most work. So technically reorgs will always go to the "most work chain", but that usually ends up being the longer chain (more blocks at the same difficulty means more work) so the misnomer "longest chain" is used.