Let the grass grow on the front lawn a little bit longer than i usually do (i've been busy of late) so had to pull out my trusty old challenge strimmer to get it down to a length that my mower could handle.
Strimming away, i heard the wire snap so looked down to see what i'd hit. I've only gone and chopped a leg off a frog

How the hell a frog ended up here i don't know? The nearest water is the canal about a third of a mile away!
Thing is the frog is still with us. It can't jump forward anymore but it's good at circles. In short should i take a spade to it's head or do i keep it safe and warm for a few weeks and release it back into the garden?
I like frogs so what's my best course of action?