Wharf announced his retirement from cricket during the 2009 County Championship, after failing to recover from a long-term injury.

[2] He never played Test cricket, but made his England One Day International debut at Trent Bridge, Nottingham, against India in 2004.

In 2011, he was added to the England and Wales Cricket Board list of reserve umpires, alongside the late Russell Evans and Billy Taylor.

[3] The next month, he stood in his first One Day International (ODI) match, between England and Australia, at Sophia Gardens in Cardiff on 16 June 2018.

[4] In October 2019, he was appointed as one of the twelve umpires to officiate matches in the 2019 ICC T20 World Cup Qualifier tournament in the United Arab Emirates.