Ben Earl kept alive his dream of back-to-back Premiership titles with different clubs in front of watching Eddie Jones.
The England back row, who joined Bristol on a season-long loan from Saracens during lockdown, played a lead role as Bears went second in the table with their biggest ever top-flight win.
Earl was named man of the match for a try, an assist and no missed tackles as Bristol scored three times in the first 18 minutes, fell asleep for half an hour, then woke to finish with a flourish.
It made for another miserable outing for Northampton, who suffered their ninth loss in 11 Premiership games.
Bears boss Pat Lam told of his pride in his side’s seven-try performance – then blasted the three-week ban handed to his captain Siale Piutau on Monday.
Piutau received the same punishment as Worcester forward Andrew Kitchener who was the aggressor and then allegedly swore at the ref after being sent off.
Lam raged: “The messages of inconsistency is what I am struggling with. The message is you can start a fight and punch someone with the same penalty – I just think there needs to be clarity and a shake up.
“You should be able to defend yourself if someone attacks you like that. What does he say to his wife and children when he gets a whack to the head? Things have got to change.”
With Piutau on the sidelines Bristol flew out of the traps, Harry Thacker scoring, Piutau’s brother Charles putting Alapati Leiua on the left and Andy Uren making it three in the space of eight minutes.
They then lost their way as Saints lost two looseheads and the game went to uncontested scrums.
It took Josh Gillespie coming off the bench to pull one try back for the visitors on his debut to re-awaken Bristol.
The Bears responded in devastating fashion to being poked, scoring four tries in nine minutes through Chris Vui, Earl, Piers O’Connor and Luke Morahan.
BRISTOL – Tries: Thacker, Leiua, Uren, Vui, Earl, O’Connor, Morahan. Cons: Sheedy 6.
NORTHAMPTON – Try: Gillespie. Con: Grayson. Pen: Grayson.