What two things can you do to prevent neighbourhood cats entering your garden or house? Is it A? Install an electronic cat flap. B? Gently shoo them away. C? Have them arrested for trespassing, or D? Spread lion manure on your garden. And the correct answers are, A, install an electronic cat flap, and B, gently shoo them away. It wasn’t C, have them arrested for trespassing, for obvious reasons. And it wasn’t D, spread lion manure on your garden. While a number of products can be used to deter cats from gardens, their efficacy is undetermined.