The Isle of Man speedster took a second successive stage victory, following his success in Dumfries on Tuesday, as he comfortably beat Steele Von Hoff into second position.
And the world champion took the gold jersey off the shoulders of Leigh Howard after the Orica-GreenEDGE rider finished third.
Crosswinds caused havoc on the run-in to the finish and the peloton split into three groups with an elite group of 27 riders coming over the line together.
“Bradley [Wiggins] lives not far from Blackpool and the route included a lot of the roads he uses for training. He told us it was very open, and very windy, and he knew the exact place we should go on the attack. It was the perfect call," said Cavendish.
“It was a grim day but we ploughed through and waited until that moment 22km from home to split things apart.
“On those last 5km along the front we just made it so fast that nobody else could get close to us.
“We’d expected a crosswind, but in the end it felt like a tailwind, and we were flying.
"Luke [Rowe]’s going for the overall so we tried to let him get a bit of a gap like the other day, but then Leigh Howard jumped so I had to go with him, and then it was quite straightforward for me in the sprint."
The break of the day featured Kristian House (Rapha Condor), Mathew Cronshaw (Node 4 - Giordana), Niklas Gustavsson (UK Youth Cycling), Dan Craven (IG - Sigma Sport), David Le Lay (Saur - Sojasun) and Ronan McLaughlin (An Post - Sean Kelly).
They escaped early on in the 156km stage from Carlisle and had built up a lead of 6:50 after 30km in wet conditions.
But their lead was whittled down as Team Sky joined Orica GreenEDGE at the head of the chasing bunch and it stood at 1:45 as they crested the third and final classified climb of the day with 42km left.
KoM leader House and Swedish youngster Gustavsson were distanced soon after with the last of the escapees, Craven and McLaughlin, absorbed with 10km remaining.
- Leigh Howard