Robson's biggest tournament win so far was at the World Darts Trophy in Utrecht, Netherlands.

This match included a leg which Tony Green and John Part touted as "probably the best in thirty years",[citation needed] which Robson won to take the fifth set and lead 3–2.

Robson lost 3–0 in a first round clash with 2009 champion and 5th seed Ted Hankey at the 2010 BDO World Championship.

The next year, Robson was seeded once more and cruised through to the quarter-finals for a third time by defeating Steve Douglas and Dave Chisnall for the loss of just one set.

Robson was knocked out of the 2012 World Championships in the first round losing 3–0 to Steve Douglas Gary was again knocked out in the first round in 2013 this time losing 3–1 to Garry Thompson He competed for a tour card at the 2020 Q school in an attempt to join the Professional Darts Corporation, however he finished 164th and failed to win a tour card.