|LV= County Championship Division One, Wantage Road|
|Close day three: Somerset 375 & 249-8d v Northants 221 & 108-5|
|Northants 4 pts, Somerset 7 pts|
Somerset are on course to keep up the pressure at the top of Division One, by dominating day three at Northants.
Visiting opener Chris Jones reached a season's-best 87 in a five-hour stay at the crease for the third-placed side.
James Hildreth (43), Lewis Gregory (40 no) and Colin Ingram (37) chipped in before declaring on 249-8, with James Middlebrook (4-40) the best bowler.
Winless Northants then slumped to 108-5 at the close, despite James Kettleborough's 58, still needing 296.
Kettleborough's efforts held up a fragile Northants second innings, after they lost Middlebrook and Richard Levi in consecutive Lewis Gregory (2-23) deliveries, caught by sub wicketkeeper Alex Barrow, who was standing in for the injured Craig Kieswetter.
Richard Newton and Matthew Spreigel then fell in quick succession to Alonso Thomas (2-25), before Kettlebough was caught at short square-leg off George Dockrell.
Bottom club Northants' hopes of taking anything from the game now rest with Kyle Coetzer and nightwatchman Olly Stone, who saw them to the close at Wantage Road facing an uphill battle on the final day.
BBC Somerset's Stephen Lamb:
"If Somerset can maintain the bowling standards they have set over the past two days, they should wrap up their fourth Championship win of the season in some comfort tomorrow.
"Lewis Gregory was excellent again, both in contributing an unbeaten 40 to ensure that Somerset extended their lead beyond 400 and enable Marcus Trescothick to declare, and then in taking two wickets in successive deliveries to send back Northants skipper James Middlebrook and Richard Levi.
"Chris Jones's 87 for the visitors was a further step in the direction of a maiden Championship hundred, while the low confidence levels in the Northants' camp were apparent when they batted in the last session of the day."