Track number 8 of Orbital's 1999 album The Middle of Nowhere. It has no lyrics as such (as few Orbital pieces do) but it is, in my opinion, Orbital's greatest work to date. It uses some rather obscure synth sounds in such a way that you really must be in a certain frame of mind to fully enjoy it.
I don't want to spoil to for those who have never listened to it, but I'll give you hint about it. One word... telephones.