REVERE – An East Boston man allegedly held up a taxi driver with a fake gun early Thursday after he was ordered to pay up front for the fare.Jason A. Watson, 25, of 77 Trenton St., was charged with assault with a dangerous weapon, gun, kidnapping. He was arraigned Thursday at Chelsea District Court by Judge Benjamin Barnes, who ordered him held without bail due to an open case. Watson is due back in court Dec 2.According to police records, a Revere officer was fueling his cruiser at the department around 1:30 a.m., when he saw a Patriot taxi pull into the station while flashing his headlights on and off in an attempt to get his attention.When the officer walked over to the taxi, the driver jumped out yelling, “He has a gun!” The officer then drew his weapon and held Watson at gunpoint while other officers were called to the scene and took him into custody.The weapon that Watson allegedly used, a Black Phantom BB gun, was found tossed in the street, about 20 feet away from the taxi. As he was being booked, police say Watson, who appeared to be under the influence of drugs or alcohol, kept saying, “It’s not a real gun” and “You know me, if I wanted to kill him, I could get a real gun.”The 44-year-old victim said he had been dispatched to Warren Street for a fare heading to East Boston, but when he picked up the passenger, Watson, he said he became suspicious and asked him to pay up front for the ride.At that point, the victim said Watson reached forward and put one hand on his left shoulder and felt a hard object pressed against his ribs. When he looked down, the victim said he saw what he believed to be a semi-automatic handgun and heard Watson repeat the address that he wanted to go to in East Boston.While on the way, the victim managed to pull into the station’s parking lot and escape from Watson.