Couple of guys in my old office used to have those Lacie orange rubber/rugged jobs with them all the time - think they come in just under a ton? Not used them myself though.
I picked up one of those a few weeks back. Seem to be relatively well regarded (you can get 4TB ones but apparently those particular ones have been prone to issues, 500GB-2TB seem to be unaffected)
BTW, they're much smaller than I was expecting, so check the size if that's a factor to consider
Can snyone recommend a good/reliable 2tb external/portable SSD for under £100?