Somerset 591 for 7 dec (Abell 142, Renshaw 94, Gregory 89, Lammonby 76, Hildreth 53) beat Gloucestershire 186 (Bracey 39, Leach 5-49) and 159 (Bethell 61, Leach 3-41) by an innings and 246 runs
Somerset steamrollered Gloucestershire's patched-up team to complete a record-breaking LV= County Championship victory by an innings and 246 runs inside three days at Bristol.
It was the Cider county's biggest ever margin of victory over their arch-rivals, which was previously by an innings and 170 at Taunton back in 1893, a match in which WG Grace featured for the visitors.
Gloucestershire, without injured skipper Graeme van Buuren, were bowled out for 186 in their first innings from an overnight 119 for 4, Jack Leach finishing with 5 for 49 from 25.4 overs.
There was no respite for a home side including three new loan signings when they followed on 405 behind beneath cloudless skies. Leach completed match figures of 8 for 90, while teenager Jacob Bethell hit 61 in a total of 159.
Somerset took 23 points to Gloucestershire's one and have now reeled off successive victories after losing their first three Championship fixtures.
With van Burren nursing a shoulder injury sustained in the field on day two, Somerset needed only five wickets at the start of the day to wrap up their opponents' first innings.
Bethell, on a one-match loan to Gloucestershire from Warwickshire, began with a sweet on-drive for four off Craig Overton and followed up with another boundary in the same over.
There was concern for Somerset when Overton was forced off by a twinge in his left knee, but the England all-rounder was able to return to bowl at the end of the innings.
Josh Davey made the breakthrough for Somerset with the total on 144, rapping Ryan Higgins on the back pad and pinning him lbw for 31, before quickly having Zafar Gofar taken at slip.
Lewis Gregory uprooted Zak Chappell's middle stump and the impressive Bethell fell leg-before on the back foot to Leach for 37 as Gloucestershire lurched to 152 for 8.
Last pair Matt Taylor and Brad Wheal offered some resistance, taking the total to 186 for 8 at lunch. Taylor finished 24 not out when Wheal fell lbw to a ball from Leach that appeared to keep low.
Gloucestershire's second innings had reached 24 in the ninth over when George Scott edged Peter Siddle straight to James Hildreth at second slip.
Marcus Harris fell on the same total, miscuing a pull shot off Overton and skying a catch to Tom Lammonby at mid-on. It was 28 for 3 when Miles Hammond nicked a ball from Davey through to wicketkeeper Steve Davies.
Higgins was caught behind for 16 trying to force Gregory off the back foot and by tea Gloucestershire were in disarray at 74 for 4.
Bethell had again given a lesson in technique to more experienced colleagues. But any hopes of a recovery disappeared in the over after the interval when James Bracey swept Leach and Tom Abell took an outstanding catch, one-handed above his head at backward square leg.
Luck continued to desert injury-plagued Gloucestershire as Bethell slipped when called for a quick single off Leach by Zafar Gohar, who was forced to turn back and failed to beat Abell's throw to the bowler's end.
Chappell was bowled off an inside edge for 20 by Overton, who then took a low catch at second slip off Leach to remove Taylor.
Bethell's mature batting in a crisis brought him a deserved half-century off 84 balls, with eight fours. But when he swept Leach into the hands of Lammonby at deep square, Somerset celebrated an overwhelming success.
Jack Leach claims eight as Somerset seal record-breaking win over Gloucestershire
Spinner backs up first-innings five-for as on-loan teen Jacob Bethell impresses in Gloucestershire's second innings
Tom Abell century tightens Somerset's stranglehold
Gloucestershire struggle to 119 for 4 in reply to visitors' 591 for 7 declared