  A measurement of the W boson mass and width has been performed by the DELPHI
collaboration using the data collected during the full LEP2 programme
(1996-2000). The data sample has an integrated luminosity of 660 pb^-1 and was
collected over a range of centre-of-mass energies from 161 to 209 GeV. Results
are obtained by applying the method of direct reconstruction of the mass of the
W from its decay products in both the W+W- -> lvqq and W+W- -> qqqq channels.
The W mass result for the combined data set is
  M_W = 80.336 +/- 0.055 (Stat.) +/- 0.028 (Syst.)
  +/- 0.025 (FSI) +/- 0.009 (LEP) GeV/c^2, where FSI represents the uncertainty
due to final state interaction effects in the qqqq channel, and LEP represents
that arising from the knowledge of the collision energy of the accelerator. The
combined value for the W width is Gamma_W = 2.404 +/- 0.140 (Stat.) +/- 0.077
(Syst.) +/- 0.065 (FSI) GeV/c^2. These results supersede all values previously
published by the DELPHI collaboration. This paper is dedicated to the memory of
Carlo Caso.
