The only venomous snakes in britain of note, (of all 3 species), is the adder/viper. this usually makes most peeps quite ill for a few days, however, some peeps can have an allergic reaction to the venom which can make them far more ill or can nudge them towards anaphylactic shock. Also peeps who are very young or very old or infirm can have more severe reactions.
Given that i have a deadly reaction to even little teeny british wasp stings, I think I wld rather be allergic to adders that go out of their way to avoid you
