We have used the Hubble Space Telescope to measure the motion in the sky and compute the galactocentric orbit of the black hole X-ray binary GRO J1655-40 .
The system moves with a runaway space velocity of 112 \pm 18 km s ^ { -1 } in a highly eccentric ( e = 0.34 \pm 0.05 ) orbit .
The black hole was formed in the disk at a distance greater than 3 kpc from the Galactic centre and must have been shot to such eccentric orbit by the explosion of the progenitor star .
The runaway linear momentum and kinetic energy of this black hole binary are comparable to those of solitary neutron stars and millisecond pulsars .
GRO J1655-40 is the first black hole for which there is evidence for a runaway motion imparted by a natal kick in a supernova explosion .