That HAS to be a Brook Trout. I believe they are the only trout to have "throat teeth" as can be seen in the second photo.
Not so dude. I caught a 'Brown' Trout out of the Ae ( Annan Trib) that was 4 lbs and it had teeth like that eg. in rows backward pointing and down the mouth like a shark. The consensus was this was a Sea going Brownie, a Bull Trout. In those days (correction 1984 - I'm even older than I think
) Brown and Sea Trout were regarded as separate species.
My specimen did not have quite so pronounced front teeth as the one above.
Anyone called Jeremy Wade yet
L