A couple of years ago Angus and Hamish were in the garden I went out to bring them in,at the back of my house I have a trellis on the wall were I used to hang a bird feed with peanuts,I was standing about four feet from it and in the corner of my eye I saw something move,when I turned round it was a rat it was feeding itself with the peanuts..I was terrified,I knocked on my neighbours door the next day to let him know there may be a problem with rats,to my amazement he said I have seen one in my garden for months I was a bit annoyed he never told me,I phoned the enviromental health out they put a black box in my garden with a little hole in the side for the rat to enter,it was very strong poison inside,my next door neighbour asked him to check his garden  they found rats nest under his shed and they were feeding themselves from his compost box as there were signs of them chewing on it and they had made a hole,he still has his compost heap  which I felt would attract more the at the back of our houses are fields/ hills/farms all countryside so they were about,I never went into my garden for a long time and never at night, luckily I have not seen another rat since *shudders* the enviromental health said  traps were banned  as it is was inhumane and  you do hear them screaming when caught in one of those *shudders*...