Abstract: Apparatus for drilling a borehole from a first subterranean location to a second subterranean location, comprises a casing (4) extending longitudinally inside a borehole, a conduit (6) extending longitudinally inside casing (4), and capable of being in sealing relationship therewith, at least one entry line (23,24) for liquid into the apparatus, a first annulus (22) between the casing (4) and conduit (6), at least one entry for liquid in the conduit, a tubing (14) having a first end and a second end (16), a remote controlled electrically powered drilling device (12) and remote controlled electrically powered pump, the device and pump being capable of being in fluid contact with the first end of the tubing (14), the second end (16) of the tubing (14) being inside the conduit (6) at a location more remote from the drilling device (12) than the entry for liquid in the conduit (6), with the conduit (6), tubing (14) and first end and second end (16) of the tubing (14) being adapted to provide routes for liquid con