Off-spinner Ollie Rayner is joining Middlesex on a three-year contract after two loan spells at Lord’s last season.
The 25-year-old is leaving Sussex, for whom he played youth and Academy cricket before joining the professional staff in 2006.
Rayner became the first Sussex batsman to score a first-class hundred on debut for 86 years, when he did so against Sri Lanka in 2006, but he has struggled to hold down a regular place in the side in any of the three formats.
He joined Middlesex on loan in May but when he returned to Hove for the Twenty20 Cup he took five wickets against Somerset and appeared set to play a significant role in the second half of the summer.
Instead, he returned to Lord’s in August and played eight County Championship games as they won promotion back to Division One.
Middlesex’s managing director of cricket Angus Fraser, said: “Ollie is an exciting and talented yung cricketer who contributes with bat, ball and in the field. He made an extremely positive impression during the loan periods he spent with us and we are delighted to have him on board.
“On several occasions he showed exactly what he is capable of producing. His unbeaten 58 at Derbyshire helped to secure a remarkable victory and he took four crucial second innings wickets in our final game of the season against Leicestershire.
“As a catcher I have seen few better than Ollie behind the wicket. Several of the catches he took had to be seen to be believed. These catches set a wonderful tone for the side and the quality of our slip catching had a huge influence on us winning Division Two of the Championship.
“Ollie has presence on the field and works extremely hard at his game. As with all young cricketers there is work to be done but he has the potential to be an extremely fine all-round cricketer. We are all looking forward to working with him on a full-time basis.”
Rayner was always likely to leave Sussex in search of regular first-team opportunities and rates his part in Middlesex’s promotion as the highlight of his career so far.
He said: “Middlesex offered me a great opportunity and I like the dynamics of the club and feel there is a place there for me to fill and grow in to.
“Being part of a young, talented and successful side is an exciting prospect for me and I am really looking forward to the challenge.”
While Rayner departs, Sussex have handed batsman Matt Machan, who took a half-century off the Indians in August, a new two-year contract. Machan also made a half-century on his Championship debut against Nottinghamshire in the final game of the season.