Bush suffered "mild to moderate" scrapes on his hands and arms that required bandages by the White House physician, said White House spokesman Scott McClellan. The accident occurred on asphalt, McClellan said. It was raining lightly at the time, and Bush was wearing a helmet.
Police said the officer suffered a "very minor" ankle injury.
The officer was on a security detail. He is a member of the police department of Strathclyde, McClellan said.
The president talked with the officer to make sure he was all right, and also asked White House physician Richard Tubb to monitor the officer's condition at the hospital.
The presidential bike suffered some damage, McClellan said, so Bush rode back to the hotel in a Secret Service vehicle.
The fall did not affect the president's schedule. Dressed in a tuxedo, he attended a dinner hosted by Queen Elizabeth at the annual Group of Eight economic summit. He showed no signs of distress.
A year ago, Bush was cut and bruised when he sailed over the handlebars while riding a mountain bike at his Texas ranch.
In 2003, he tried out a Segway, the standup, motorized scooter at the family's seaside estate in Maine. It went down on his first attempt, but he stayed on his feet with a flying leap over the machine. Undeterred, he got on again and cruised around the driveway with his father.