  Using data taken as part of the Isaac Newton Telescope Wide Field Camera (INT
WFC) survey of M31, we have identified an arc-like overdensity of blue,
presumably metal-poor, red giant branch stars in the north-west quadrant of
M31. This feature is approximately 1 degree (15 kpc) in extent and has a
surface brightness of Sigma_V' ~ 28.5 +/- 0.5 mags per sq. arcsec. The arc
appears to emanate from the dwarf elliptical galaxy NGC205, and the colour of
its red giant branch is significantly different to the M31 disk population but
closely resembles that of NGC205. Further, using data taken with the DEep
Imaging Multi-Object Spectrograph (DEIMOS) on Keck II, we identify the radial
velocity signature of this arc. Its velocity dispersion is measured to be
approximately 10km/s, similar to that of the central regions of NGC205 and
typical of stellar streams. Based upon the spatial coincidence of these
objects, the surface brightness, the velocity dispersions and the similarity in
colour of the red giant branches, we postulate that the arc is part of a
stellar stream, the progenitor of which is NGC205.
