Reece Topley, the left-arm pace bowler, is to leave Essex and join Hampshire on a two-year deal. Paul Grayson, the coach, is also leaving the club, while the future of the captain, James Foster, is uncertain.

Topley, 21, who made his England debut in the T20 against Australia in Cardiff, rejected the offer of a new contract from Essex and was the subject of interest from eight other counties. It is understood that Hampshire did not offer the most money, but Topley was impressed by the plans of chairman Rod Bransgrove and the coach Giles White and felt the environment at the club would help him fulfil his potential.

His signing in the face of so much competition - Surrey, Warwickshire and Worcestershire were among the other interested counties - represents something of a coup for Hampshire. Topley, a tall left-arm swing bowler, has outstanding red and white ball statistics for his age. He was the standout bowler at the 2012 Under-19 World Cup in Australia, is currently the leading wicket taker in this year's Royal London Cup with 20 wickets and has 125 first-class victims at a cost of 25.78.

Topley, who burst onto the professional scene in 2011 with successive five wicket hauls when just 17 and still at school, has said his ultimate ambition is to become the first left-arm pace bowler to claim 100 Test wickets for England.

Leaving Essex will be a major wrench, though. Not only has he progressed through the club's system - he has been there since he was nine - but his father, Don Topley, also represented the club for a decade as a bustling seam bowler and still commentates on the club for local radio.

"I am extremely sad to be leaving Essex having played for the county since the age of nine and have thoroughly enjoyed my time in a great dressing room," Topley said. "I would like to publicly thank all the players for their huge support and firm friendships.

"In particular, I must also thank the two 1st XI coaches: Paul Grayson for the fantastic opportunity he has given me and to Chris Silverwood, who I have great admiration for and enjoyed working with."

It is understood Reece was unsettled by changes at the club. Since the return of Ronnie Irani as chairman of the cricket committee, the future of the coach, Grayson, has looked especially uncertain - ESPNcricinfo understands he is no longer working with the team while a severance package is agreed - with Irani his probable replacement.

Grayson was appointed coach in July 2007. While Essex won the Friends Provident Trophy in 2008, they have not made the progress some expected since and currently sit mid-table in Division Two. Grayson's supporters would argue, however, that he has never held much real power and was not given the authority to sign new players or agree contract terms.

The future of the captain, Foster, is also unclear with the former England keeper understood to have received offers of employment from outside the game, including a role at a local private school. Topley remains close and appreciative of Grayson and Essex bowling coach, Chris Silverwood, but has a less obvious rapport with Irani. It could well be that Topley joins Hampshire on loan before the end of this season.

It continues a worrying trend for Essex. While the club - perhaps as a result of its densely populated catchment area - has a fine record of producing talented players, Topley joins a list that includes Varun Chopra, Ben Foakes, Adam Wheater, Tony Palladino, Billy Godleman, Chris Wright and Tymal Mills as talented players who have recently left the club to pursue their county careers elsewhere.

They are likely to sign another seamer - Surrey's Tim Linely - as replacement for Topley, but losing a 21-year-old and gaining a 33-year-old - whatever his merits - is unlikely to impress Essex supporters.