  We present a detailed comparison between ONETEP, our linear-scaling density
functional method, and the conventional pseudopotential plane wave approach in
order to demonstrate its high accuracy. Further comparison with all-electron
calculations shows that only the largest available Gaussian basis sets can
match the accuracy of routine ONETEP calculations. Results indicate that our
minimisation procedure is not ill-conditioned and that convergence to
self-consistency is achieved efficiently. Finally we present calculations with
ONETEP, on systems of about 1000 atoms, of electronic, structural and chemical
properties of a wide variety of materials such as metallic and semiconducting
carbon nanotubes, crystalline silicon and a protein complex.
