At first I thought this was odd but then I remembered that macOS introduced new security rules some time back and applications were required to be given access to do certain operations. In this case, the Terminal.app application didn't have Full Disk Access.
This was easily resolved, from the System Preferences, I clicked on Security & Privacy...
From there I scrolled down to Full Disk Access and clicked the lock icon at the bottom left to unlock changes being made. This required me to enter my password.
Afterwards I could select Terminal to have full disk access, but it required me to quite the app first, which I did.
Trying the same thing out in Terminal again let me list the contents of Trash!