Lancashire 140 (Jennings 56, Overton 4-32, Gregory 4-50) and 398 (Wells 130, Bohannon 60, Leach 3-57) beat Somerset 146 (Bailey 4-36, Balderson 4-50) and 224 (Vaughan 68, Wells 4-36) by 168 runs
Surrey's third successive Vitality County Championship title was confirmed when Lancashire took just 32 minutes and 7.1 overs on the fourth morning to complete their 168-run victory over Somerset at Emirates Old Trafford.
Resuming on 204 for 6, Somerset were dismissed for 224 with Luke Wells taking two of the wickets to finish with 4 for 36 and Anderson Phillip the other two to finish with 3 for 81.
The result ends Somerset's hopes of a breakthrough County Championship title, and is their second disappointment in the space of a week. On Saturday, their defence of their Vitality Blast title ended in defeat in the final against Gloucestershire, although they still have one last shot at silverware with the Metro Bank One-Day Cup final against Glamorgan looming at the weekend.
"If you don't believe you can win a game, there's no point turning up," Jason Kerr, Somerset's head coach, said. "We thought there was a chance today but obviously it hasn't turned out that way."
"I take a huge amount from this season," Kerr added. "Every county wants to be in a position in which you are competing to win trophies and there's also been young players emerging. There'll be a huge number of positives but it's probably slightly early to be in a position where we can reflect on it all.
"I think we've progressed massively since last year. We finished seventh last year and this year we've been more disjointed with our overseas signings and the continuity of the side's been different as well but I think we've grown massively."
Somerset lost a wicket to the first ball of the day when Lewis Gregory was deceived by Wells' googly and bowled for a golden duck.
Next over, Lancashire enjoyed more success when Craig Overton was leg before wicket to Anderson Phillip for 4 and after pulling Wells for two fours, Brett Randell was bowled for 9 when trying to repeat the feat. The game ended and Surrey's title was confirmed when James Rew was bowled off an inside edge by Phillip for 31
Collectors of statistical oddities might wish to note that this is the first match in the history of the County Championship in which 21 wickets have fallen on the first day and the game has lasted until the fourth morning without weather interruption.
Despite their win, Lancashire are still favourites to be relegated. Keaton Jennings' side will be playing Division Two cricket next season regardless of the result of their game against Worcestershire if Nottinghamshire take ten points from their final match at home to Warwickshire, who would also need five points from that game.
"It's been a really good game of cricket," Jennings said. "A good surface, two teams competing over the course of four days. It's been good fun.
"I'm really chuffed the lads have put in what I think is our best team performance over the course of this campaign. It's really pleasing. It's down to guys putting their hands up. Luke Wells getting 130 and putting in a performance that the team required to try and get us into a winning position and then taking poles this morning.
"Guys chipped in with the new ball; Anderson, Bails, Will, Baldy. The bowlers had to take 20 wickets to win the game and they've done that. It's been an entertaining three and a bit days, so it just shows you cricket at Old Trafford has been really good.
"It's awesome what the guys have produced over the last three days. I thought both sides were under par first innings, it wasn't a 140 surface. I also didn't think it was a 400 surface either which we got.
"All in all, both sides competed and made errors to let each other back into the game. We could have disintegrated, but didn't. We continued to fight like we have over the whole campaign. The guys have tried really hard, they just haven't quite got it right like we did this game."
