Thompson told MUFC Online "Marcus was a player high on my list of possible summer signings, he offers a lot as he holds the ball up well, brings players into the game and importantly for us he'll get his share of goals.
Thompson added "I'm chuffed to have signed Marcus, I've done my best to keep our interest in him quiet and to finally have signed him is a boost and another step forward for the club."
Duharty now in his third spell at Cossham Street came to the fore in the 2008/09 season scoring nine goals in seven games for Cadbury Heath which led to a move to Mangotsfield United, then managed by Spencer Thomas and Paul Milsom.
Duharty's stay at Cossham Street was short lived, moving to Bridgwater Town in January 2009 where his performances earned him a move to Blue Square South Weston Super Mare ahead of the 2010/11 season.
Last season after returning from injury Duharty enjoyed a succesful loan spell at Cossham Street scoring five goals during a two month loan period.