Sussex are facing the prospect of their first defeat of the season after losing 15 wickets on the third day of their Championship clash with Somerset at Hove.

The division one leaders were forced to follow-on after being dismissed for 142 in their first innings and reached the close on 162-6, still trailing by 68.

Lewis Gregory has been the chief destroyer for Somerset taking seven wickets in the match so far with only Luke Wells and Ed Joyce showing any resistance.

Wells carried his bat in the first innings – the first Sussex batsman to do so in ten years – and was unbeaten on 79 when he ran out of partners in the afternoon session.

Joyce will need to do the same in the second innings if Sussex are to stand a chance of saving the game and was 76 not out at stumps.

Gregory ripped through the Sussex batting in the morning after Alfonso Thomas had bowled Mike Yardy for ten in the fourth over of the day.

The all-rounder picked up the wickets of Rory Hamilton-Brown (0), Matt Machan (10) and Ben Brown (4) in a fiery spell down the hill to leave Sussex reeling on 61-5.

He returned to remove Chris Jordan for five after lunch and James Anyon for two with Jamie Overton picking up the wickets of Ashar Zaidi – much to the batsman’s disgust – and Steve Magoffin.

Jon Lewis added 36 for the final wicket with Wells who followed up his half century in the second innings at Edgbaston by batting for 168 balls.

Somerset skipper Marcus Trescothick had no hesitation in enforcing the follow-on and was rewarded when Wells was finally dismissed as Sussex reached tea on 62-1.

Alfonso Thomas then picked up the wickets of Yardy (11) and Hamilton-Brown (4) before Gregory got rid of Machan (7) and Brown (1).

Zaidi put on 42 with Joyce for the sixth wicket before being superbly caught by sub wicketkeeper Alex Barrow off the bowling of Jamie Overton.

Joyce was still there at the end with Jordan (6 not out) but will need to make his fourth first class century of the season if Sussex are to avoid defeat.