A 20-year-old D.C. Jail inmate escaped from a security van yesterday as he was being transferred from the jail to the Montgomery County Detention Center in Rockville, the U.S. Marshals Service reported.

Chief Deputy U.S. Marshal Roger Ray said Phillip Robinson, who has been charged with burglary and theft in the District and with other crimes in Maryland, was in the van with nine other inmates who were being taken to D.C. Superior Court. He was to have been transferred there to a car for the trip to Montgomery County, Ray said.

Ray said the van arrived at the jail to pick up the inmates about 9 a.m., and that Robinson's absence was apparently discovered when the van reached the court about noon. Robinson was unable to say what time the van actually left the jail, or what route it took to the court.

Such vans are fitted with wire-mesh enclosures, and the van's back gate is supposed to be locked from the outside, Ray said. Inmates being moved in the vans are handcuffed to one another in pairs, he said.

Officials speculated that Robinson, a small man who weighs about 130 pounds, may have been able to slip the handcuff from his wrist and squeeze through a 12-inch space that separates the wire mesh enclosure from the top of the van. There is also a small space at the top of the rear gate, officials said.