The last active volcanos in the British Isles were way before
humanity, however, the Icelandic volcanos have had
effects both in Scotland and Ireland with shards of volcanic glass
found in peat in both countries corresponding to Icelandic
erruptions. Dust clouds would certainly come and cause strange
lighting in the sky. Theories exist that one of the big Icelandic volcanos
were responsible for the principal depopulation of the Scottish
highlands about 6000 years ago by a climatic change from mediterranean
to present day conditions in a single generation. The BBC broadcast
a documentary about this called "Time of Darkness" about 3 years ago.
Anyway, to sum up, no volcanos since well before the rise of man.