In the triumvirate of couch potatoes known as the Bit Torrent Rebel Alliance, Michael is only now catching up on 'Life On Mars'. Overnight, we watched the episode in which Sam Tyler sought to bring down a corrupt crime lord who used his nightclub as a front.
During the investigation, DCI Gene Hunt warned Sam off, saying that he was "Living in Cloud Cuckoo Land" if he thought he could put an end to Stephen Warren's criminal activities.
Cloud Cuckoo Land refers to an (unrealistically) idealistic state where everything is perfect. ("You're living in Cloud-cuckoo-land.") It hints that the person referred to is naïve, unaware of reality or deranged in holding such an optimistic belief.
The reference is to the play, "The Birds" by the Athenian playwright Aristophanes, in which Pisthetairos (which can be translated to mean "Mr. Trusting") and Euelpides (which can be translated to mean "Mr. Hopeful") with the help of Tereus, tired of the Earth and Olympus, decide to erect a perfect city between the clouds, to be named Cloud-Cuckoo-Land.