Transferred (not by choice) from O2 to Sky 14 February. Still using O2 router. Thought nothing of it really but noticed that downloads appeared slow. Did a TBB speed test; found that speed had dropped from about 15 M on O2 to around 7. Read a lot on various forums about other people having the same problem and not getting an answer. 10 minute on-line chat with Sky on 21 (or 22 February - can't remember) concluded that problem was down to incompatibility with O2 router and they would send a Sky one. Sky router arrived on 25 February. Speed back up to 17 M. Very efficient hassle-free service.