Not enough room to swing a cat in | You cannot swing a cat (here, there, etc.).
Idiom meaning: have very little physical room to move about / very little space available / the place is very small.
Example in sentence
But you can't possibly live and work in this tiny flat. There isn't enough room to swing a cat. ('English Idioms and How to use Them', Jennifer Seidle, W. McMordie)
Origin
The reference may be to the old days of flogging in the Royal Navy, when a man was taken on the deck for the punishment, there being not room enough in the confined space below for the swing of the whip (cat o' nine tails).
However, there is another explanation that cat is a corruption of cot. A sailor spending a night ashore was given a room in a boarding-house which was so small that, as he explained to his shipmates next day, there was not enough room to swing a cot in. The point of the story is that a sailor's hammock, which is swung,was called in those days his cot.