Leicestershire 338 and 86 for 1 trail Sussex 694 for 9 dec (Simpson 205*, Lamb 134, Karvelas 54) by 270 runs

New captain John Simpson struck a maiden double-century as Sussex put Leicestershire to the sword on day three of their Vitality County Championship clash, piling up the third-highest total in their first-class history before declaring on 694 for 9.

Leicestershire closed on 86 for 1 in their second innings, trailing by 270.

Former Middlesex wicketkeeper Simpson finished on 205 not out, having shared a seventh-wicket partnership of 255 with fellow Lancastrian Danny Lamb, another new face at the south coast club, whose 134 was also a career-best.

Ari Karvelas came in at No. 10 to crack 55 off 40 balls and it was with his dismissal six overs after tea that Sussex declared with a first-innings lead of 356 in reply to Leicestershire's 338 all out, with 24 overs left in the day.

With the insurance of a second innings available, Simpson clearly hoped his bowlers could dismiss Leicestershire for a second time in what remains of the match, although the weather forecast for the final day suggests there may be interruptions to play.

It was a dispiriting day for Leicestershire, whose bowlers had done an effective containing job with the old ball in Saturday's final session before taking two important wickets with the new one, leaving Sussex six down and still 56 runs behind.

One more wicket while the second ball was still hard at the start of the third morning would have exposed the Sussex tail - but that wicket simply didn't come. Indeed, apart from one sustained but firmly rejected appeal for a gloved caught behind by Ben Mike against Lamb, there was barely a hint of a breakthrough until five overs after lunch when Lamb, on 85, did get a bat to a leg-side delivery from Matt Salisbury but Ben Cox, diving to his left, could only help it to the boundary.

By that time, the seventh-wicket pair had added 150 to Sussex's burgeoning total, 133 of which had come during as one-sided a morning session as this ground is likely to witness all year. The Kookaburra ball is clearly no friend of bowlers in English April conditions and this one sat up to be hit far too often.

Lamb lifted it over the boundary rope four times in the session. On the third occasion, when Lamb slog-swept the spinner Liam Trevaskis over the seats on the popular side and the ball was temporarily lost, Leicestershire were handed a replacement, but it was no more responsive.

Simpson reached his fifty from 108 balls and his hundred from 197, passing the bigger milestone when he swivel-pulled Salisbury for his 15th four, his 11th century in first-class cricket. The shot brought up the Sussex 450 for good measure.

Lamb, who moved from Lancashire over the winter, was quicker to a hundred than his partner by some distance, needing just 108 balls, adding 10 fours to the four sixes. Judging by the numbers crowding on to the Sussex balcony to applaud as he scampered through for a couple off Trevaskis before raising his bat, he is already a popular figure in his new dressing room.

Lamb thanked them with some high entertainment, bringing out the scoop for six number five off Mike, launching Trevaskis high over long-on to chalk up the 500 with his sixth maximum (equalling his old career-best of 125), and reverse-sweeping Louis Kimber, Leicestershire's part-time offspinner, for his seventh.

Little wonder that when his luck finally ran out - he was bowled attempting to heave Trevaskis over midwicket - he walked back to the pavilion grinning from ear to ear. For the record, Lamb was the former Durham left-arm spinner's maiden Leicestershire wicket, although figures of 1 for 192 might slightly take the gloss off it.

There was no end to Leicestershire's ordeal, however. Jack Carson hit two sixes in a 23-ball 38 and Simpson flexed his muscles to add five sixes to 23 fours, his second hundred coming off 97 balls, before calling time on the innings when Karvelas was caught at long-off from Kimber's bowling.

Leicestershire negotiated the first 14 overs of the second innings without mishap, Rishi Patel having been dropped on 19, until the introduction of Carson brought a breakthrough as the offspinner's first ball induced an inside edge on to pad as Australian opener Marcus Harris was caught at short leg.