1/1 live game.
UTG, we see

. We make it £4. We start with £250
Chap two to my left (£230) has been a bit odd pre so far (I have been here an hour). He makes it £16. Young lad to my right is new (£170ish) but has been fairly aggro. He flats BB. I decide to call (wrongly but it's a cash game...)
Flop

Check check to aggressor. He checks.
Turn

BB now bets £31
I call. Aggressor also calls.
River
BB now shoves his c£120.
As per the thread title, what's our play?