Marcus Trescothick hit his eighth LV County Championship century of a prolific season to put Somerset in a strong position on the second day at Taunton.

The former England opener took his first-class run tally to 1,745 for the summer by making 102 in a total of 266 for three. Arul Suppiah hit 95 as the pair produced their eighth century stand of the season.

Earlier, Lancashire had been bowled out for 344 after resuming on 297 for five.

First-day centurion Paul Horton was out for 175 as Charl Willoughby claimed five for 109 and Ben Phillips four for 46.

Willoughby's efforts took him past 50 first class wickets for the season, a feat the South African left-arm seamer has achieved in all of his four years as a Somerset player.

It was the home side's day from the moment Kyle Hogg was caught at first slip by Trescothick off Willoughby without adding to his overnight 69.

Glen Chapple was lbw to Willoughby for a duck and Saj Mahmood was dropped in the slips before being caught at cover by Suppiah off Alfonso Thomas the ball after being forced to change his bat.

It was 330 for nine when Horton's magnificent effort ended, caught behind looking to hook Willoughby, having faced 287 balls and hit 28 fours.

Somerset wicketkeeper Craig Kieswetter picked up his sixth catch of the innings to dismiss Oliver Newby for 13 and Lancashire had added only 47 to their overnight score in excellent batting conditions.

Trescothick needed a few moments of fortune and survived some close appeals, but also produced some thumping trademark shots.

His half-century included 48 in boundaries, nine fours and two sixes off Gary Keedy, one of which sailed into the stand named after him at the County Ground.

He fell to the fourth ball after tea, bowled by Mahmood off an inside edge trying to leave the ball. By then the scoreboard read 193 and Trescothick had faced 145 balls, extending his boundary count to 18 fours and two sixes.

Suppiah, already past 1,000 runs in his best ever season, lost nothing by comparison and had hit 16 fours and a six in his 178-ball innings when he lost his off stump to Chapple.

James Hildreth fell cheaply to Mahmood, who bowled well after tea, but Zander de Bruyn was 36 not out when shadows across the pitch ended play five overs early and debutant Jos Buttler overcome a nervous start to be unbeaten on 13.