the 60-year-old joined the company as plane refueller in december 2007 , three decades after he was medically discharged from the british army 's parachute regiment .
his job involved kneeling down , removing a manhole cover and connecting the fuel pipe to refuel planes .
mr gibson claims that he was subjected to a tirade of ` horrible harassment ' while working at h and g contracting services ltd at heathrow airport .