Clifford entered the professional scene when recruited by Sir
Clive Woodward in December 2004, with the long term plan being to become his assistant coach at
Southampton. Woodward met with Clifford before they went into football together to learn from the methods he was using and to look at the work he was doing with the soccer schools. Clifford was appointed Head of Sport Science and head coach of the U21s, working with a crop of youth team players that included Gareth Bale, Nathan Dwyer, Theo Walcott and more. After falling out with the coaching establishment at Southampton and leaving his role, he returned to the non-league club he owned,
Garforth Town, as manager. In 2003 Clifford purchased the
Northern Counties East Football League club
Garforth Town. At the time of the purchase, Clifford expressed the desire to take the club, then at the ninth level of the
football pyramid, into the English Football League within twenty years. The club gained two promotions during Clifford's first two full seasons as manager. Within the six years, they managed to reach the EvoStik Premier League - the highest level in the clubs' history. Clifford signed several well-known players including:
Lee Sharpe, and
Careca. In April 2009, Garforth reached the final of the West Riding County Cup to face
Bradford Park Avenue. Garforth won 5-4 on penalties to claim the cup. After three seasons of managing
Garforth Town, Clifford made the decision to step aside as manager of his club. In September 2008, Clifford was approached by a South African consortium looking to purchase Newcastle United Football Club, with the party offering the 38-year-old a role as Technical Director as well as shares in the club. In 2017, Clifford began working within HN Sports agency, and in 2019 moved over to Blue Sky Sports football agency. Clifford has worked with Blue Sky Sports since its inception, in the role of elite performance coach. == Integer Football ==