Tom Lammonby struck his third century in as many matches as Somerset and Essex set up a barnstorming finale in the Bob Willis Trophy.

Weston Mercury: Somerset's Tom Lammonby in action during day four of the Bob Willis Trophy Final at Lord's, London.Somerset's Tom Lammonby in action during day four of the Bob Willis Trophy Final at Lord's, London. (Image: PA Wire/PA Images)

Opening batsman Lammonby only made his first-class bow last month but effortlessly collected 116 at Lord’s.

The 20-year-old helped Somerset to 227 for seven and a lead of 191, but wickets from evergreen duo Jamie Porter (4-51) and Simon Harmer (2-79) stunted their progress ahead of the final day.

Somerset simply need to bowl Essex out to win the title on the last day, while the reigning county champions can draw the match to claim the Bob Willis Trophy, due to scoring more runs in the first innings.

Lewis Gregory had called the first half an hour on the fourth day “big” during his post-play interviews on Friday – with Essex requiring 31 more runs to claim the important first-innings lead.

Weston Mercury: Somerset's Ben Green in action during day four of the Bob Willis Trophy Final at Lord's, London.Somerset's Ben Green in action during day four of the Bob Willis Trophy Final at Lord's, London. (Image: PA Wire/PA Images)

It proved anti-climatic as nightwatchman Porter and Adam Wheater comfortably wiped out the deficit in 44 balls and 31 minutes.

Gregory had a ‘big’ following 10 minutes when he uprooted Porter’s middle stump and had Harmer caught at second slip. The fast bowler ended with six for 72, as Essex concluded their 120 over innings on 337 for eight, a lead of 36.

In response, Somerset returned to credit in little more than 12 overs, with Lammonby punishing Porter for back-to-back boundaries in the embryonic stage of his innings.

Lammonby would have watched team-mate Eddie Byrom and Sir Alastair Cook’s centuries during the opening three days of the encounter but instead of replicating their often-gritty efforts, he found a flow.

Weston Mercury: Somerset’s Lewis Gregory celebrates bowling out Essex’s Jamie Porter during day four of the Bob Willis Trophy Final at Lord's, London.Somerset’s Lewis Gregory celebrates bowling out Essex’s Jamie Porter during day four of the Bob Willis Trophy Final at Lord's, London. (Image: PA Wire/PA Images)

After a watchful start against the new ball which had caused issues in their first innings, he and Ben Green soon pushed the run-rate to around 3.5 runs an over before the latter edged Aaron Beard to Cook at first slip after a 105-run stand.

Exeter-born Lammonby made his Somerset debut in last season’s Vitality Blast but was forced to wait until 2020 for his first appearance in red ball cricket.

A 41 in his first innings showed promise, but hundreds in the last two group games against Gloucestershire and Worcestershire – in which he carried his bat – demonstrated his young talent.

He reached his 73-ball half-century with a paddled sweep before he produced a stunning string to move from 63 to 92 in 13 balls – helped by three successive boundaries off Beard.

That coincided with a 47-ball 50 partnership with Tom Abell, before the Somerset captain clipped Porter to square leg.

Lammonby raised his bat and helmet on his century after a flick to mid-wicket after an chanceless 134 deliveries, before bettering his previous best of 107.

Then Porter and Harmer, who now have 65 wickets between them in the competition, combined to decimate the Somerset middle-order.

First-innings century-maker Byrom was the first to depart in a sequence under the lights, which saw four wickets fall in 47 balls, when he chopped Porter on.

The eye of the hurricane was a 10-ball spell which saw the back of George Bartlett, Lammonby and Lewis Gregory for a single run.

Bartlett pulled Porter to Tom Westley at mid-on, Lammonby was lbw to Harmer and then Cook snatched a flying catch to dismiss Gregory off Porter.

Craig Overton, who was dropped by sub fielder Ben Allison at fine leg on nine, and Steven Davies rebuilt slowly with a 36-run stand.

But Davies gave Cook his third catch of the day at first slip soon before bad light brought play to a premature end with six overs left in the day.