Hi Graham,
Funny enough, we had the same problem tonight on our Servis washer/dryer. I removed the top of it (it is held on by two screws on the back) and there is a clearly visible red button. Pushed this down and it worked fine (I think it is some sort of thermal/overload cutout). Failing this, on your Hotpoint, if it is an old machine, it could be the element (does the water heat when it is washing ?). I know we have a different model, but the principle is the same, you should be able to reset the "cutout".
Ferg., April 2004