Yesterday someone dumped three boxes containing what I presume are large canisters of Nitrous Oxide in front of an alley way in between my neighbour at 19 Thaxted Road and myself at 21 Thaxted Road SE9 3PU. My neighbour is concerned they are liable to be able to explode and neither of us know what to do about it. I am in my 70's and he and his wife in their 80's and so unable to move them even if we wanted to. We are unsure what to do now and so hence my reporting on here. I didnt know what category to report this in either and so apologies if it is the wrong one.