simply chopping the platter in half wouldn’t remove the data”
and confirmed that it could be recovered – but the costs of retrieving any
remaining information “would be prohibitive”. That’s because you’d need
“something along the lines of an electron scanning microscope” to read the data
from the remains of the platter – and those currently sell second-hand for at
least £40,000.
Tanfield-Johnson also confirmed that, once you’d cracked open
a hard disk to extract the platters within, recovering any data would become
even more difficult, because you’d need “the same model and make of [circuit]
board” to access each track of data on the disk. So, unless you’re willing to
spend tens of thousands of pounds, it looks like your data is safe.