It all went wrong for Taunton when they had centre-back Owen Irish sent-off just before half-time. Larkhall, beaten 10-2 at Taunton earlier this season, took advantage of the extra man to score three times in the second half through Joe Raynes with two and Greg Peel.
Taunton remain second but third-placed Tiverton Town have reduced the gap between the sides to two points after they beat fourth-placed Salisbury at Ladysmead in front of a crowd of 322.
Jamie Price gave Tivvy the boost of an early first-minute lead that he eventually doubled with 17 minutes remaining.
The runaway Bulls won 4-1 at Edgar Street against North Leigh to take another step towards the title, another great crowd of 2,474 seeing the visitors take a shock third minute lead through Matt Sysum.
But the home side weren`t behind for long as top scorer John Mills levelled seven minutes later. Mark Preece then gave the Bulls an interval lead with a 42nd minute second before second half goals from Pablo Haysham and a late Tristan Plummer penalty sealed a comfortable afternoon`s work for Peter Beadle`s side.
Evesham United maintained fifth spot after a 2-0 win at Bishops Cleeve, Mark Magee three minutes after half-time and then Adam Mann 15 minutes from time the United scorers.
Swindon Supermarine and Mangotsfield United still have chances of a top five spot with wins on Saturday leaving them five and six points respectively behind Evesham.
Supermarine won 4-1 at the WebbsWood Stadium against a Bideford AFC side who hadn`t lost in nine games.
They came back from a 15th minute Ben Watson goal down to win thanks to Brad Hooper`s penalty after 32 minutes, a Josh Parsons brace in the 37th and 84th minutes and Ryan Campbell two minutes later.
The Mangos won 1-0 at third-bottom AFC Totton, courtesy of a 63rd minute Liam Monelle effort while Bridgwater Town are all-but doomed after losing 1-0 at second-bottom Wantage Town.
They were left 21 points behind AFC Totton with only 21 on offer now after Todd Hatherway`s 39th minute goal proved decisive for the Alfredians, who are still 14 points adrift themselves.
Elsewhere, Will Morford bagged a brace in the 73rd and 83rd minutes – the second from the spot – as Shortwood United won 2-1 at Wimborne Town, for whom Billy Maybury had given them an 18th minute lead.
Slimbridge`s Lee Smith was another two-goal man as his 32nd and 76th minute strikes saw off Paulton Rovers 2-0 at home while James Blake`s spot-kick and Lee Francis 10 minutes from time proved enough for Barnstaple Town in a 2-1 win at home to Didcot Town despite Adam Learoyd's reply 20 minutes from time.
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